Symposium Organizers
D. Kurt Gaskill, U.S. Naval Research Laboratory
Adam Gali, Hungarian Academy of Sciences
Brenda VanMil, U.S. Army Research Laboratory
Joerg Wrachtrup, University of Stuttgart
Symposium Support
U.S. Army Research Laboratory-Army Quantum Science and Engineering Program
ED1.1/ED12.1: Joint Session I: Solid-State Quantum Matter I
Session Chairs
Tuesday PM, April 18, 2017
PCC North, 100 Level, Room 132 A
11:30 AM - *ED1.1.01/ED12.1.01
Creating Quantum Technologies with Spins in Semiconductors
David Awschalom 1
1 , University of Chicago, Chicago, Illinois, United States
Show AbstractThere is a growing interest in exploiting the quantum properties of electronic and nuclear spins for the manipulation and storage of information in the solid state. Such schemes offer fundamentally new scientific and technological opportunities by leveraging elements of traditional electronics to precisely control coherent interactions between electrons, nuclei, and electromagnetic fields. Although conventional electronics avoid disorder, recent efforts embrace materials with incorporated defects whose special electronic and nuclear spin states allow the processing of information in a fundamentally different manner because of their explicitly quantum nature [1]. These defects possess desirable qualities – their spin states can be controlled at and above room temperature, they can reside in a material host amenable to microfabrication, and they can have an optical interface near the telecom bands. Here we focus on recent developments that exploit precise quantum control techniques to explore coherent spin dynamics and interactions. In particular, we manipulate and measure the geometric (Berry) phase of a single spin in diamond using all-optical control techniques [2], and investigate the robustness of this control pathway to noise as well as its viability for implementations of photonic networks of quantum states. Separately, we find that defect-based electronic states in silicon carbide can be isolated at the single spin level [3] with surprisingly long spin coherence times, can achieve near-unity nuclear polarization [4] and be robustly entangled at room temperature [5]. Finally, we identify and characterize a new class of optically controllable defect spin based on chromium impurities in the wide-bandgap semiconductors silicon carbide and gallium nitride [6].
[1] D.D. Awschalom, L.C. Bassett, A.S. Dzurak, E.L. Hu and J.R. Petta, Science 339, 1174 (2013).
[2] C. G. Yale, F. J. Heremans, B. B. Zhou, et al., Nature Photonics 10, 184 (2016); BB. Zhou et al., Nature Physics, accepted (2016).
[3] D. J. Christle, A. L. Falk, P. Andrich, P. V. Klimov, et al., Nature Materials 14, 160 (2015); D. J. Christle et al., (2016).
[4] A. L. Falk, P. V. Klimov, et al., Physical Review Letters 114, 247603 (2015).
[5] P. V. Klimov, A. L. Falk, D. J. Christle, V. V. Dobrovitski, and D. D. Awschalom, Science Advances 1, e1501015 (2015).
[6] W. F. Koehl et al., arXiv:1608.08255 (2016).
12:00 PM - *ED1.1.02/ED12.1.02
Single Photon Emitters—Diamond and Beyond
Igor Aharonovich 1
1 , University of Technology Sydney, Ultimo, New South Wales, Australia
Show AbstractOver the last decade diamond has emerged as a promising platform for quantum technologies due to its ability to host plethora of quantum emitters. While initial research has been focused predominantly on the NV center in diamond, several alternative promising candidates have emerged over the last decade.
In this talk I will review the recent progress on the SiV defect in diamond and show that even small nanodiamonds can host nearly transform limited emitters. I will show how to couple these emitters to cavities and show promising avenues to trigger them electrically.
At the second part of my talk I will review other platforms that host previously unexplored single emitters – namely two dimensional (2D) hexagonal boron nitride. This promising atomically thin van der waals material can host ultra bright defect that can be engineered in bulk and in a monolayer. I will show our recent results on characterizing them and eingeering them using ion implantation and electron beam irradiation techniques. I will also discuss the challenges and the advantages of working with quantum emitters in a 2D platform.
12:30 PM - *ED1.1.03/ED12.1.03
Single Photon Sources in Silicon Carbide
Alexander Lohrmann 1 , Timothy Karle 1 , Stefania Castelleto 2 , Naoya Iwamoto 3 , Marco Negri 4 , Matteo Bosi 4 , Jeffrey McCallum 1 , Adam Gali 5 6 , Takeshi Ohshima 3 , Brett Johnson 1
1 , University of Melbourne, Melbourne, Victoria, Australia, 2 , RMIT University, Melbourne, Victoria, Australia, 3 , National Institutes for Quantum and Radiological Science and Technology, Takasaki Japan, 4 , IMEM-CNR Institute, Parma Italy, 5 , Hungarian Academy of Sciences, Budapest Hungary, 6 , Budapest University of Technology and Economics, Budapest Hungary
Show AbstractSingle defects in silicon carbide have unique properties amenable to applications in emerging quantum technologies such as quantum cryptography and quantum information processing. Understanding the formation of isolated single defects, their properties and atomic identity is a challenging and active area of research. In addition, single defect integration into devices to allow their properties to be modified, enhanced or efficiently addressed also presents some interesting obstacles.
We have recently discovered a new class of color center that can be employed as a single photon source and can be formed in a number of different SiC polytypes (3C, 6H, 4H) by a simple oxidation procedure. Photons emitted from these centers are highly polarized, within the visible wavelength range, photo stable and can be produced at high count rates. Interestingly, despite having properties suggestive of a high symmetry defect, they show a spectral variability which cannot be explained by a point defect with multiple charge states or possible lattice sites. This suggests that a more complex structure or interaction is operative. Although direct evidence for their atomic origin remains elusive, detailed measurements suggest that they exist very close to the SiC/SiO2 interface. Defects on the Si and C-face also show subtle differences that may significantly narrow possible candidate structures.
Having explored the optical properties of these surface-related single photon sources we also leverage the mature device fabrication protocols available for SiC to integrate them into both electrical light emitting diodes and photonic structures. The electroluminescence of a pn junction single photon emitting diode formed by ion implantation also displays fully polarized output, excellent photon statistics (with a count rate of >300 kHz), and high stability in both continuous and pulsed modes, all at room temperature. A unique method to accurately position and align the polarization dipole of a single defect within a micro-disk resonator is also demonstrated. All methods employed here are equally compatible with other SiC defects. These results provide a foundation for the possible large-scale integration of single photon sources into a broad range of emerging quantum applications.
ED1.2/ED12.2: Joint Session II: Advanced Spin Control for Quantum Technology
Session Chairs
Tuesday PM, April 18, 2017
PCC North, 100 Level, Room 132 A
2:30 PM - *ED1.2.01/ED12.2.01
Color Centers Coupled to Nanobeam Cavities in 4H Silicon Carbide—Beyond "Simple" Resonant Enhancement
Evelyn Hu 1 , David Bracher 1 , Xingyu Zhang 1 , Rodrick Defo 1 , Efthimios Kaxiras 1
1 , Harvard University, Cambridge, Massachusetts, United States
Show AbstractSilicon carbide (SiC) has recently garnered attention for its spin-coherent, luminescent defect centers (color centers), occurring in a variety of polytypes. Coupling of these color centers to high quality optical cavities can augment the photonic signature of the defect, allowing for longer-distance, robust information transfer of the color center state. In addition, the optical cavities can serve as exquisitely sensitive “nanoscopes” with the spatial and spectral resolution necessary to uncover details of the atomic environment of the rich set of defects within the SiC lattice.
We have fabricated numerous high-quality factor (Q) nanobeam photonic crystal cavities (PCC) in 4H-SiC, whose resonant frequencies have been designed to match either divacancy centers with photoluminescence (PL) emission ranging from 1070-1300 nm or negatively charged silicon vacancy centers with PL emission spanning 860-1100 nm. The best coupling conditions require a match between the frequency of the cavity mode and color center emission, as well as an overlap between color center position and the spatial extent of the cavity mode.
Color centers were introduced into fabricated one-dimensional nanobeam PCC’s either through ion implantation or electron irradiation. Subsequent thermal annealing resulted in improvements in the cavity Qs, as well as changes in the intensities of the cavity modes, likely due to alteration of the cavity-defect coupling as the defects move within the cavity. We believe the cavities thus provide a means of sensitively monitoring the spatial migration of defects. Work is ongoing to model the stability and migration behavior of silicon vacancies in 4H-SiC. Ultimately, detailed understanding of such behavior may provide insights into approaches for deterministic placement of defects within the cavity.
3:00 PM - *ED1.2.02/ED12.2.02
Theory of Dynamic Nuclear Polarization through Hybrid Registers in Diamond and SiC
Viktor Ivady 1 2 , Igor Abrikosov 1 , Adam Gali 2
1 , Linköping University, Linköping Sweden, 2 , Wigner Research Centre for Physics, Budapest Hungary
Show AbstractElectron spin-nuclear spin hybrid registers in semiconductors exhibit rapidly increasing potential in diverse entanglement based applications thanks to the long nuclear spin coherence time and the electron spin's addressability. Point defect quantum bits (qubits) in diamond and silicon carbide (SiC) have stood out in implementing such registers. The coupling of the spins in hybrid registers makes efficient dynamic nuclear polarization (DNP) possible, which can lead to near unity nuclear spin initialization fidelity as well as to the hyperpolarization of the host material.
In my talk, I discuss the theoretical model and simulations of DNP processes that utilize efficient nuclear spin-electron spin coupling either in the excited or in the ground state of point defect qubits. I show that the different lifetime of the excited and ground states causes different characteristics of the DNP processes. Through this realization recent experimental observations can be understood. Furthermore, I show that in the ground state process the longer lifetime allows weakly coupled hybrid registers, which can exhibit a magnetic field dependent, reversible polarization process. By such mechanism, radio-frequency-free manipulation of nuclear spins’ initial state is possible.
3:30 PM - *ED1.2.03/ED12.2.03
Silicon Vacancies in Silicon Carbide as a Novel Quantum System
Sang-Yun Lee 1 2 , Matthias Widmann 1 , Matthias Niethammer 1 , Roland Nagy 1 , Ian Booker 3 , Pontus Stenberg 3 , Olof Kordina 3 , Li-Ping Yang 4 , Nguyen Son 3 , Ivan Ivanov 3 , Nan Zhao 4 , Ilja Gerhardt 1 , Cristian Bonato 5 , Sophia Economou 6 , Takeshi Ohshima 7 , Adam Gali 8 , Erik Janzen 3 , Joerg Wrachtrup 1 9
1 3rd Institute of Physics, University of Stuttgart and Stuttgart Research Center of Photonic Engineering (SCoPE) and IQST, Stuttgart Germany, 2 Center for Quantum Information, Korea Institute of Science and Technology, Suwon-si, Gyeonggi-do Korea (the Republic of), 3 Department of Physics, Chemistry and Biology, Linköping University, Linköping Sweden, 4 , Beijing Computational Science Research Center, Beijing China, 5 Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh United Kingdom, 6 Department of Physics, Virginia Tech, Blacksburg, Virginia, United States, 7 , National Institutes for Quantum and Radiological Science and Technology, Takasaki Japan, 8 , Wigner Research Centre for Physics, Budapest Hungary, 9 , Max Planck Institute for Solid State Research, Stuttgart Germany
Show AbstractDiamond has been known as a successful host material embedding defect based quantum systems. The well-known examples are point defects, e.g. the NV centers, which possess long-lived electronic and nuclear spins whose detection is possible thanks to their efficient control and coupling to the fluorescence properties. Silicon carbide (SiC) also features promising properties similar to diamond such as the wide bandgap in which deep defects can exist without interfering with other electronic states. It also provides a diluted spin bath due to the zero nuclear spin of the naturally abundant carbon-12 and silicon-28, and the low concentration of paramagnetic impurities in high purity SiC single crystals. Among many point defects, which recently have been successfully isolated, the silicon vacancy (VSi) is one of the attracting quantum systems in SiC since strong spin-dependent recombination allows optical detection of electronic spin states which are also long-lived [1,2]. In this presentation, we will introduce how one can create single VSi defects, and optically readout their coherent spin state. We will also present how the VSi can be used for quantum metrology, e.g. vector magnetometry [3,4]. Finally, the coherent optical and spin properties studied at low temperature will be introduced to discuss the possibility of use of the VSi in SiC as a qubit for integrated quantum computing and communication devices.
[1] M. Widmann et al., Coherent control of single spins in silicon carbide at room temperature. Nat Mater. 14, 164–168 (2015).
[2] L.-P. Yang et al., Electron spin decoherence in silicon carbide nuclear spin bath. Phys. Rev. B. 90, 241203 (2014).
[3] S.-Y. Lee, M. Niethammer, J. Wrachtrup, Vector magnetometry based on S=3/2 electronic spins. Phys. Rev. B. 92, 115201 (2015).
[4] M. Niethammer et al., Vector Magnetometry Using Silicon Vacancies in 4H-SiC Under Ambient Conditions. Phys. Rev. Appl. 6, 34001 (2016).
4:00 PM - ED1.2/ED12.2
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ED1.3/ED12.3: Joint Session III: Spintronics and Optomechanics
Session Chairs
Brett Johnson
Ren-Bao Liu
Tuesday PM, April 18, 2017
PCC North, 100 Level, Room 132 A
4:30 PM - *ED1.3.01/ED12.3.01
Nanomechanical Sensing Using Spins in Diamond
Marcus Doherty 1
1 , Australian National University, Canberra, Australian Capital Territory, Australia
Show AbstractIn this presentation, I will report preliminary steps towards realising highly sensitive nano-spin-mechanical sensors (NSMS) using nitrogen-vacancy (NV) defect centers in diamond nanomechanical structures. Such NSMS represent a new class of nanomechanical sensor that combines the well-established quantum nanometrology techniques of the NV center with mechanical sensing techniques from NEMS. By doing so, NSMS have novel nanometrology applications, such as combined on-chip mass spectrometry and magnetic resonance imaging of single molecules. The novel applications of NSMS will mostly likely benefit the fields of cellular biomechanics and molecular biochemistry. However, it is also possible that this new class of sensor will have diverse applications that are yet to be conceived.
5:00 PM - *ED1.3.02/ED12.3.02
Nuclear Spintronics in Silicon Carbide
Abram Falk 1 2 , Paul Klimov 2 , David Christle 2 , Hosung Seo 2 , Giulia Galli 2 , David Awschalom 2
1 , IBM T.J. Watson Research Center, Yorktown Heights, New York, United States, 2 Institute for Molecular Engineering, University of Chicago, Chicago, Illinois, United States
Show AbstractNuclear spins in room-temperature liquids were among the first platforms explored for executing quantum algorithms. However, the small nuclear magnetic moment, which gives nuclei their long-lived spin coherence, also prevents them from reaching a large polarization in equilibrium. For instance, even at 25 mK and in a 10-T magnetic field, only 10% of thermalized 29Si nuclei will be polarized. In this talk, I will show how optically pumped dynamic nuclear polarization can align 99% of nuclear spins at specific SiC lattice sites in ambient conditions [1, 2]. I will then discuss how this high polarization allows us to produce an ensemble of genuinely entangled electron-nuclear spin pairs [3]. Finally, I’ll discuss how the binary atomic nature of the SiC crystal can suppress nuclear spin flip-flops, leading to unusually long electron spin coherence times that exceed 1 ms [4]. These results lay a foundation for hyperpolarized magnetic-resonance-imaging probes and quantum networks of nuclear spins.
[1] Falk et al., Phys. Rev. Lett. 114, 247603 (2015).
[2] Ivady et al., arXiv:1605.07931 (2016)
[3] Klimov et al., Sci. Adv. 1, e1501015 (2015).
[4] Seo et al., Nat. Commun. 7, 12935 (2016)
5:30 PM - *ED1.3.03/ED12.3.03
Tunneling-Mediated Charge Transfer between Nitrogen-Vacancy Centers and Nitrogen Impurities in Type-1b Diamond
Siddharth Dhomkar 1 , Jacob Henshaw 1 , Pablo Zangara 1 , Audrius Alkauskas 2 , Carlos Meriles 1
1 , City College of New York, New York, New York, United States, 2 , Center for Physical Sciences and Technology, Vilnius Lithuania
Show AbstractWe use confocal microscopy to examine the ionization of negatively charged nitrogen-vacancy (NV-) centers in nitrogen-rich diamond. We find that the fluorescence time trace of micron-sized NV- ensembles under red excitation depends on the illumination history. In particular, we show that continued exposure to weak green light for long time intervals dramatically alters the NV- effective ionization rates. We interpret these observations in terms of a tunneling-enabled process of charge transfer between NVs and surrounding nitrogen impurities, a phenomenon we tackle for the first time using ab-initio calculations and Monte Carlo modeling. Our study suggests that the asymmetry between ‘light-induced’ and ‘dark’ charge tunneling leads to preferential charge depletion in the nanoscale vicinity of the NVs, a form of trapped charge heterogeneity that seems to underpin our observations. These results complement prior studies on the charge dynamics of individual NVs, and serve as a platform for future NV charge control experiments in the presence of co-existing defects.
Symposium Organizers
D. Kurt Gaskill, U.S. Naval Research Laboratory
Adam Gali, Hungarian Academy of Sciences
Brenda VanMil, U.S. Army Research Laboratory
Joerg Wrachtrup, University of Stuttgart
Symposium Support
U.S. Army Research Laboratory-Army Quantum Science and Engineering Program
ED1.4/ED12.4: Joint Session IV: Solid-State Quantum Matter II
Session Chairs
Wednesday AM, April 19, 2017
PCC North, 100 Level, Room 132 A
9:00 AM - *ED1.4.01/ED12.4.01
Engineering Single-Photon Sources in Hexagonal Boron Nitride
Lee Bassett 1
1 , University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractLow-dimensional materials hosting single spins and single photon sources can provide unique functionality for quantum technologies due to intrinsic spatial confinement and the ability to create multifunctional layered materials. One such example is hexagonal boron nitride (h-BN), a two-dimensional wide-bandgap semiconductor that hosts isolated single-photon sources exhibiting visible fluorescence at room temperature. An understanding of the physics underlying h-BN’s quantum emission is critical to the realization of new applications with this material, together with reliable methods for defect creation and identification and control of environmental perturbations. To that end, we have studied the optical properties of quantum emitters in exfoliated, single-crystal h-BN and their creation via electron bombardment and high-temperature annealing [1]. Spectral, temporal, polarization, and spatial characteristics of the defects’ emission point to complex electronic and chemical structure, and comparisons of emission from free-standing and supported h-BN membranes indicate strong substrate interaction effects. The measurements constrain possible defect models and will aid in the development of precision quantum sensors, nanophotonic devices, and other quantum technologies based on h-BN and layered materials.
[1] A. L. Exarhos, D. A. Hopper, R. R. Grote, A. Alkauskas, and L. C. Bassett, ACS Nano, Article ASAP, DOI: 10.1021/acsnano.7b00665
This work was supported by the Army Research Office (W911NF-15-1-0589) and NSF MRSEC (DMR-1120901).
9:30 AM - *ED1.4.02/ED12.4.02
Engineering of Highly Coherent Spin Defects in Silicon Carbide
Vladimir Dyakonov 1 , Dmitrij Simin 1 , Hannes Kraus 1 , Andreas Sperlich 1 , Takeshi Ohshima 2 , Georgy Astakhov 1
1 , University of Wuerzburg, Wurzburg Germany, 2 , National Institutes for Quantum and Radiological Science and Technology, Takasaki Japan
Show AbstractIn oder to achieve long-lived electron spin coherence in solid state, expensive and non-trivial engineering with spin-free nuclear isotopes is usually required.We demonstrate that silicon carbide (SiC) even with natural isotope abundance can preserve a coherent spin superposition in silicon vacancies over unexpectedly long time approaching hundred milliseconds. This spin locking is attained through the suppression of heteronuclear spin cross-talking by applying a magnetic field above ten millitesla in combination with dynamic decoupling from nuclear spin baths. We also find that the spin-lattice relaxation time, which is the ultimate limit for spin coherence, tends to ten seconds at cryogenic temperature. Our approach may be extended to other polyatomic compounds and lead to improvement of quantum sensors based on spin-locking protocols.
10:00 AM - *ED1.4.03/ED12.4.03
Spins in Silicon Carbide for Quantum Technologies
Paul Klimov 1 , Abram Falk 1 2 , David Christle 1 , Hosung Seo 1 , Viktor Ivady 3 4 , Adam Gali 4 , Giulia Galli 1 , David Awschalom 1
1 Institute for Molecular Engineering, University of Chicago, Chicago, Illinois, United States, 2 T.J. Watson Research Center, IBM, Yorktown Heights, New York, United States, 3 Department of Physics, Chemistry and Biology, Linköping University, Linköping Sweden, 4 Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest Hungary
Show AbstractOver the past several decades, silicon carbide has established itself as a versatile material platform for high-power electronics, optoelectronics, and micromechanical devices. These technologies have been driven by advanced device processing capabilities, and the availability of large-area, single-crystal wafers. Recent advances have also established silicon carbide as a promising host for a novel class of quantum technologies based on the spin of intrinsic color centers, with the potential of leveraging existing device fabrication protocols alongside solid-state quantum control. Among these color centers are the divacancies. These color centers have built-in optical interfaces near the telecommunication wavelengths and highly coherent electron spins associated with them that can be manipulated with magnetic, electric, optical, and strain fields. In this talk I will discuss how these electron spins can be interfaced with the nuclear spins of 13C and 29Si isotopic defects to form multi-spin systems, which are attractive for many prospective quantum technologies [1]. Although nuclear spins are a primary source of decoherence in this system [2], the hyperfine interaction can be used to initialize [3, 4, 5], manipulate, and measure them, establishing them as a valuable resource. I will conclude the talk with an outlook and discuss important challenges in this rapidly developing field.
[1] Klimov et al., Sci. Adv. 1, e1501015 (2015).
[2] Seo et al., Nat. Commun. 7, 12935 (2016)
[3] Falk et al., Phys. Rev. Lett. 114, 247603 (2015).
[4] Ivady et al., Phys. Rev. B. 92, 115206 (2015).
[5] Ivady et al., arXiv:1605.07931 (2016)
10:30 AM - *ED1.4.04/ED12.4.04
Towards Coherent Manipulation of Single NV Spins Using Hybrid Photoelectric MR Detection
Milos Nesladek 1 , Michal Gulka 1 , Emilie Bourgeois 1
1 , imec Leuven & Hasselt University, Diepenbeek Belgium
Show AbstractRecently demonstrated photoelectric detection of NV magnetic resonances (PDMR) in diamond (1) opens pathways towards realisation of electrical diamond quantum chips with a scalable architecture. An essential advantage compared to ODMR is the detection rate enhancement, the device miniaturisation and integration. Here we demonstrate development of robust electro-optical protocols for coherent control and readout of spins applied to shallow N-implanted quantum-grade diamond. We discuss the device fabrication and optimisation, the charge carrier injection and the characteristics of the photoelectric gain, allowing establishing highly sensitive detection. We downscale the detection from large ( > 1000) to small ensembles of several spins ( < 5 ) and outline the prospect towards the single spin detection and device fabrication. We discuss the S/N ratio and analyse the mechanism for the electronic noise and its spectrum. Basic pulsed protocols (Rabi, Ramsay, Hahn) are demonstrated and benchmarked to ODMR.
(1) Bourgeois E. et al., Nat. Com. 6, doi: 10.1038/ncomms9577 (2015)
(2) Bourgeois E. et al., arXiv:1607.00961 (2016)
11:00 AM - ED1.4/ED12.4
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ED1.5/ED12.5: Joint Session V: Advanced Spin Control for Sensing
Session Chairs
Wednesday PM, April 19, 2017
PCC North, 100 Level, Room 132 A
11:30 AM - *ED1.5.01/ED12.5.01
Advanced Spin Control for Enhanced Sensing Using NV Centers in Diamond
Nir Bar-Gill 1 , Dmitry Farfurnik 1 , Andrey Jarmola 2 , Linh Pham 3 , Zhihui Wang 4 , Viatcheslav Dobrovitski 5 , Ron Walsworth 3 6 , Dmitry Budker 7 2
1 Applied Physics and Physics, Hebrew University, Jerusalem Israel, 2 Physics, University of California, Berkeley, Berkeley, California, United States, 3 Physics, Harvard University, Cambridge, Massachusetts, United States, 4 Chemistry, University of Southern California, Los Angeles, California, United States, 5 , Ames Laboratory, Ames, Iowa, United States, 6 , Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, United States, 7 Helmholtz Institute Mainz, Johannes Gutenberg University, Mainz Germany
Show AbstractNitrogen-Vacancy (NV) color centers in diamond provide a unique nanoscale quantum spin system embedded in a solid-state structure. As such they are well suited for studies in a wide variety of fields, with emerging applications ranging from quantum information processing to magnetic field sensing and nano-MRI (Magnetic Resonance Imaging).
In this talk I will describe our research into understanding and controlling these systems, with the goal of enabling fundamental research and future applications. I will present the techniques used for manipulation of the NV centers, and for enhancing their quantum coherence lifetime. Specifically, I will describe our recent work on extending the coherence time of arbitrary quantum states, achieving 30 ms coherence times at low temperatures. I will then present our recent work on modulated continuous driving, as well as on polarization transfer schemes, relevant in the context of quantum sensing.
12:00 PM - *ED1.5.02/ED12.5.02
Novel Sensing Schemes for Frequency Tracking and Resolution
Alex Retzker 1
1 Hebrew University of Jerusalem, Racah Institute of Physics, Jerusalem Israel
Show AbstractPrecise time-keeping is critical to measurements of energy, distance, frequency and fundamental constants. In spectroscopy, time-keeping precision defines the spectral resolution. Ultimately, measurement accuracy is limited by the stability of the measuring clock. In quantum metrology, where the phase of a qubit is used to detect external fields, the qubit coherence time defines the clock stability, and therefore the measurement linewidth and precision. In this talk I will present a quantum sensing protocol for classical fields where the measurement linewidth goes beyond the sensor coherence time and is limited by the stability of a classical oscillator. Using this technique it is possible to observe a precision in frequency estimation which scales as T^{-3/2}. The high spectral resolution diamond magnetometer was applied to sensing of nanoscale magnetic fields with an intrinsic frequency resolution of 600µHz. with single quantum coherent spins in diamond.
12:30 PM - *ED1.5.03/ED12.5.03
Nitrogen-Vacancy Diamond Sensor—Novel Diamond Surfaces and Interaction with Spins
Adam Gali 1 2 , Jyh-Pin Chou 1 , Viktor Ivady 1 3 , Zoltan Bodrog 1 , Peter Udvarhelyi 1 4
1 , Hungarian Academy of Sciences, Budapest Hungary, 2 Department of Atomic Physics, Budapest University of Technology and Economics, Budapest Hungary, 3 , Linköping University, Linköping Sweden, 4 , Roland Eötvös Science University, Budapest Hungary
Show AbstractHere we present recent ab initio simulation results on realistic novel diamond surfaces, in order to optimize the spin and optical properties of shallow nitrogen-vacancy (NV) centres for sensor applications. In addition, we analyse the interaction between densely engineered NV centres by finding the critical distance where the NV centres may form NV “molecules”. In addition, we show analysis of the interaction of nearby NV centres and substitutional nitrogen donors in diamond or spins at the diamond surface that might be useful in understanding the spinpolarization of other spin centres in diamond such as N3V defect.
We have recently developed a detailed model for the optical dynamic nuclear spinpolarization (ODNP) of defects in diamond and silicon carbide that can simultaneously take into account the polarization in the ground and excited electronic state regimes. We shall briefly discuss the ODNP for different qubits in diamond and silicon carbide with various zero-field-splitting and hyperfine coupling parameters.
ED1.6/ED12.6: Joint Session VI: Sensing of Single Spins
Session Chairs
Patrick Maletinsky
Jean-Francois Roch
Wednesday PM, April 19, 2017
PCC North, 100 Level, Room 132 A
2:30 PM - *ED1.6.01/ED12.6.01
Sensing Single Molecular Spins
Joerg Wrachtrup 1 2
1 , University of Stuttgart, Stuttgart Germany, 2 , Institute for Quantum Science and Technology, IQST, Stuttgart Germany
Show AbstractDiamond defect centers are capable of sensing single electron and nuclear spins. Detecting nuclear magnetic resonance is getting a wide-spread technique. Yet, diamond defect center spin detected nuclear magnetic resonance so far misses the required spectral resolution to detect chemical shift or J coupling. In my talk I will demonstrate chemical shift resolution of both proton and fluorine nuclear spins. Currently, there are only few reports on detecting electrons spins. Mostly this is because either moleculear electron spins tend to be unstable under optical illumination and other paramagnetic species, like defects in solids, are challenging to position close to diamond spin centers. Well chosen molecular spins, however prove to be excellent systems to be detected by diamond spin sensors. I will describe our recent progress towards detecting single spins on proteins and show how to measure spin-spin coupling on proteins.
3:00 PM - *ED1.6.02/ED12.6.02
Single-Molecule Electron Spin Resonance Spectroscopy by Diamond Sensor
Fazhan Shi 1
1 Department of Modern Physics, University of Science and Technology of China, Hefei China
Show AbstractSingle molecule science and technology have unique abilities to probe molecular structure, dynamics and function, unhindered by the averaging inherent in ensemble experiments. Single molecule science is one of the ultimate goals in magnetic resonance and will has great applications in a broad range of scientific areas, from life science to physics and chemistry. To achieve the scientific goal, we choose single spins in solids based on NV defect center in diamond - (NV) as the sensitivity magnetic probe. Ultra-long spin coherence time for such qubits, even at room temperature, enables it is ultra-sensitivity to external magnetic noise with characteristic frequency.
We and co-workers successfully obtained the first single-protein spin resonance spectroscopy under ambient conditions [1], realized atomic-scale structure analysis of single nuclear-spin clusters in diamond [2], succeeded in detection of (5nm)3 hydrogen nuclear spin magnetic resonance spectroscopy [3] and detection of a single dark electron spin[4]. In the work on the single-protein magnetic resonance spectroscopy[1], the NV center in diamond is used to detect a nitroxide labeled protein and gained the magnetic resonance spectrum of single protein through electron spin resonance under ambient conditions. We not only revealed the position and orientation of the spin label relative to the NV center, but also elucidate the dynamical motions of the protein on the diamond surface. Now, we are detecting the coupling signal of electron spin pairs on a single molecule.
References:
[1] Fazhan Shi, Qi Zhang, Pengfei Wang, Hongbin Sun, Jiarong Wang, Xing Rong, Ming Chen, Chenyong Ju, Friedemann Reinhard, Hongwei Chen, Joerg Wrachtrup, Junfeng Wang, and Jiangfeng Du. Single-protein spin resonance spectroscopy under ambient conditions, Science, 347, 1135 (2015)
[2] Fazhan Shi, Xi Kong, Pengfei Wang, Fei Kong, Nan Zhao, Renbao Liu, and Jiangfeng Du. Sensing and atomic-scale structure analysis of single nuclear spin clusters in diamond, Nature Physics, 10, 21 (2014)
[3] Tobias Staudacher, Fazhan Shi, S. Pezzagna, Jan Meijer, Jiangfeng Du, Carlos A. Meriles, Friedemann Reinhard, Joerg Wrachtrup. Nuclear magnetic resonance spectroscopy on a (5nm)3 volume of liquid and solid samples, Science, 339, 561 (2013)
[4] Fazhan Shi, Qi Zhang, Boris Naydenov, Fedor Jelezko, Jiangfeng Du, Friedemann Reinhard, and Joerg Wrachtrup. Quantum logic readout and cooling of a single dark electron spin, Phys. Rev. B, 87, 195414 (2013)
3:30 PM - ED1.6/ED12.6
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4:30 PM - *ED1.6.03/ED12.6.03
Quantum Sensing and Imaging with Diamond Color Centers
Fedor Jelezko 1
1 Institute of Quantum Optics, University Ulm, Ulm Germany
Show AbstractTBA- Please provide abstract body as soon as possible
5:00 PM - *ED1.6.04/ED12.6.04
Coherent Few-Spin Systems in Diamond Nanocrystals for Quantum Sensing
Helena Knowles 1
1 , University of Cambridge, Cambridge United Kingdom
Show AbstractA system consisting of a bright spin coherently coupled to a dark spin cluster has been at the heart of many exciting proposals in recent years, from implementations of spin chains to environment-assisted schemes that enhance the performance of a single-spin magnetic field sensor1,2. Realised in a nanodiamond crystal such a cluster could transform the performance of a unique sensing device that enables temperature and magnetic field measurements inside living cells. Experimental progress on this front has been promising, albeit hindered by the limited ability to polarise, control and readout dark spins.
In this talk I will show how we use the nitrogen-vacancy centre in diamond (NV) to polarise and probe individual spins of a cluster formed of three nitrogen (N) electron spins surrounding the NV. We locate the N spins to within a few lattice sites and report the first observation of coherent spin exchange between NV and N electron spins3, essential for any exploitation of such multi-spin systems. Key to the success of these experiments is the use of a nanodiamond particle, which provides a contained spin ensemble, leading to reduced spin polarisation diffusion4.
I will also show our ability to address and coherently control nuclear spins close to the NV centre. The long coherence times provided by nuclear spins allow for enhanced sensitivity of such a hybrid system, which is of particular interest for NV centres in diamond nanocrystals as they typically have short coherence times (~μs) compared with their bulk counterparts (~ms). We observe a coherence time enhancement of two orders of magnitude for the NV-nuclear spin coupled system in diamond nanocrystals.
[1] G. Goldstein et al. PRL 106 140502 (2011), [2] N. Yao et al. Nat. Commun. 3 800 (2012), [3] H. Knowles et al. PRL 117 100802 (2016), [4] H. Knowles et al. Nat. Mater. 13 21-25 (2014)
5:30 PM - *ED1.6.05/ED12.6.05
Nanoscale Imaging of Current Density with A Single-Spin Magnetometer
Kevin Chang 1 , Alexander Eichler 1 , Jan Rhensius 1 , Luca Lorenzelli 1 , Marius Palm 1 , Christian Degen 1
1 , ETH Zurich, Zurich Switzerland
Show AbstractSingle defects in diamond, especially the nitrogen vacancy impurity (NV center), can serve as sensitive probes for magnetic fields with nanoscale spatial resolution. In this talk, we will summarize recent efforts at exploiting single NV centers for visualizing current flow in metal nanowires and carbon nanotubes [1]. Using a scanning apparatus, we are able to measure and reconstruct both DC and microwave currents with spatial resolutions down to below 30 nm. Current density imaging offers a new route for studying electronic transport and conductance variations in two-dimensional materials and devices, with many exciting applications in condensed matter physics.
References:
[1] K. Chang, A. Eichler, and C. L. Degen, Nanoscale imaging of current density with a single-spin magnetometer, arXiv:1609.09644.
ED1.7: Poster Session
Session Chairs
Thursday AM, April 20, 2017
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - ED1.7.01
Single Spins in Silicon Carbide—Coherent Control, Charge State Manipulation and Photonic Structures
Matthias Widmann 1 , Sang-Yun Lee 2 , Matthias Niethammer 1 , Torsten Rendler 1 , Roland Nagy 1 , Stefan Lasse 1 , Ian Booker 3 , Cristian Bonato 4 , Ilja Gerhardt 1 5 , Marina Radulaski 6 , Jingyuan Zhang 6 , Konstantinos Lagoudakis 6 , Takeshi Ohshima 7 , Jelena Vuckovic 6 , Nan Zhao 8 , Ivan Ivanov 3 , Nguyen Son 3 , Adam Gali 9 , Erik Janzen 3 , Joerg Wrachtrup 1 5
1 , 3rd Institute of Physics, University of Stuttgart and Stuttgart Research Center of Photonic Engineering (SCoPE) and IQST, Stuttgart Germany, 2 , Center for Quantum Information, Korea Institute of Science and Technology, Suwon-si, Gyeonggi-do, South Korea, Suwon-si, Gyeonggi-do Korea (the Republic of), 3 Department of Physics, Chemistry and Biology (IFM) / Semiconductor Materials (HALV), University of Linköping, Linköping Sweden, 4 , Heriot-Watt University, Edinburgh, United Kingdom, Edinburgh United Kingdom, 5 , Max Planck Institute for Solid State Research, Stuttgart Germany, 6 , E. L. Ginzton Laboratory, Stanford University, Stanford, California, United States, 7 , National Institutes for Quantum and Radiological Science and Technology, Takasaki Japan, 8 , Beijing Computational Science Research Center, Beijing China, 9 Department of Theoretical Solid State Physics, Institute for Solid State Physics and Opics, Wigner RCP of the H.A.S., Budapest Hungary
Show AbstractAtomic scale defects in solids have attracted a great amount of interest over the last decade, because their spins show a great potential to be used as room-temperature quantum bits (qubits) for quantum information processing and as highly sensitive sensors for electric and magnetic fields [1,2] and temperature [3]. Leading systems are color centers in diamond, e.g. the negatively charged NV center, and impurities in silicon. Single spins in diamond have coherence times in ms-range and can be read out optically at room temperature. Electrical readout is known to be possible, but single spin detection remains challenging. Spins in silicon can be driven and read out electrically very well, however only at low temperatures. Silicon carbide (SiC) can combine the advantages of both diamond and silicon, offering single spins accessible optically at room temperature embedded in a well-developed high performance electronic material. Spins in SiC can also be optically detected at a single spin level [4] at ambient conditions, but electrical detection [5] and electrical driving spin resonance [6] are possible as well. Here we extend our studies towards electrical manipulation of its charge state in order to obtain more insight about creation of isolated defects with desired spin quantum numbers. We additionally aim to bring spin systems in SiC closer to applications. To make a step towards applications, a scalable nanofabrication process, which allows us to enhance the optical properties by the use of wafer-scale photonic structures with embedded single spin defects, will be presented.
[1] M.Niethammer et al., Vector Magnetometry Using Silicon Vacancies in 4H-SiC Under Ambient Conditions, Phys. Rev. Applied 6, 034001.
[2] J. Wrachtrup, A. Finkler, Single spin magnetic resonance, J. Magn. Reson. 269 (2016) 225–236.
[3] A.N. Anisimov et al., Optical thermometry based on level anticrossing in silicon carbide, Sci. Rep. 6 (2016) 33301.
[4] M. Widmann, S.-Y. Lee, et al., Coherent control of single spins in silicon carbide at room temperature, Nat Mater. 14 (2015) 164–168.
[5] M.S. Dautrich, P.M. Lenahan, A.J. Lelis, Identification of trapping defects in 4H -silicon carbide metal-insulator-semiconductor field-effect transistors by electrically detected magnetic resonance, Appl. Phys. Lett. 89 (2006) 45–48.
[6] P.V. Klimov et al., Electrically Driven Spin Resonance in Silicon Carbide Color Centers, Phys. Rev. Lett. 112 (2014) 87601.
9:00 PM - ED1.7.02
Pure Nanodiamonds for Vacuum Levitated Optomechanics
Angelo Frangeskou 1 , Anis Rahman 3 1 , Laia Gines 2 , Soumen Mandal 2 , Oliver Williams 2 , Peter Barker 3 , Gavin Morley 1
1 , University of Warwick, Coventry United Kingdom, 3 , University College London, London United Kingdom, 2 , Cardiff University, Cardiff United Kingdom
Show AbstractOptical trapping at high vacuum of a nanodiamond containing a nitrogen vacancy centre would provide a test bed for several new phenomena in fundamental physics [1-7]. However, the nanodiamonds used so far have absorbed too much of the trapping light, heating them to destruction (above 800 K) except at pressures above 10 mbar where air molecules dissipate the excess heat [8]. We show that milling CVD diamond of 1000 times greater purity creates nanodiamonds that do not heat up even when the optical intensity is raised above 700 GW/m2 below 5 mbar of pressure [9]. We attribute the previously observed heating in commercial nanodiamonds predominantly to nitrogen defects within the diamond. Milling rather than etching bulk diamond creates large quantities of nanodiamonds, which is a requirement of many injection methods used in optical levitation (e.g. spraying from a nebulizer). These nanodiamonds should also provide longer spin coherence (T2) times than commercially available material. The ability to fabricate large quantities of pure nanodiamonds may therefore have potential applications in bio-sensing.
[1] A. Albrecht, A. Retzker, M. B. Plenio, Phys. Rev. A 90, 033834 (2014).
[2] M. Scala, M. S. Kim, G. W. Morley, P. F. Barker, S. Bose, Phys. Rev. Lett. 111, 180403 (2013).
[3] Z. Q. Yin, T. Li, X. Zhang, L. M. Duan, Phys. Rev. A 88, 033614 (2013).
[4] C. Wan, M. Scala, S. Bose, A. C. Frangeskou, A.T. M. A. Rahman, G. W. Morley, P. F. Barker, M. S. Kim, Phys. Rev. A 93, 043852 (2015).
[5] C. Wan, M. Scala, G. W. Morley, A. T. M. A. Rahman, H. Ulbricht, J. Bateman, P. F. Baker, S. Bose, M. S. Kim, Phys. Rev. Lett. 117, 143003 (2016).
[6] A. Albrecht, A. Retzker, F. Jelezko, M. B. Plenio, New J. Phys. 15, 083014 (2013).
[7] J. C. Riedel, Phys. Rev. D 88, 116005 (2013).
[8] A. T. M. A. Rahman, A. C. Frangeskou, M. S. Kim, S. Bose, G. W. Morley, P. F. Barker, Sci. Rep. 6, 21633 (2016).
[9] A. C. Frangeskou, A. T. M. A. Rahman, L. Gines, S. Mandal, O. A. Williams, P. F. Barker, G. W. Morley, arXiv:1608.04724
9:00 PM - ED1.7.03
Behavior of Nitrogen-Related Luminescence Centers in Laser-Cut Single-Crystalline Diamond under Irradiation of keV Electron Beam
Kenji Maruoka 1 , Taiki Naito 1 , Osamu Maida 1 , Toshimichi Ito 1
1 , Osaka University, Suita, Osaka, Japan
Show AbstractCurrently the nitogen-vacancy (NV) defect in diamond is expected to be applied to quantum bits working even at room temperature. Although NV centers are formed relatively easily in N-contained diamond, the removal of these centers is generally difficult. We have found that several N-related cathodoluminescence (CL) centers appear at 389 nm, 503 nm (H3 center), 575 nm (NV0 center) and so on in single-crystalline Ib diamond cut by means of a YAG laser irradiation process, followed by suitable hydrogen plasma treatment, and that these CL peaks substantially change in intensity by irradiatting the sample with 15-keV electron beam (EB). The 389-nm center originating from a pair of substitutional N atom and interstitial C atom grew while V-related CL centers were reduced with increasing EB doses. These inditcate that both the process-induced C interstitials and the Vs in the Ib diamond rather easily moved to more preferential positions to form stabler defect states, being sugggestive of possibility to control densities of NV and related centers.
9:00 PM - ED1.7.04
Structures and Emission Properties of Transition Metal Color Centers in Diamond
Nicholas Gothard 2 , Douglas Dudis 1 , Luke Bissell 1
2 , University of Dayton Research Institute, Dayton, Ohio, United States, 1 , Air Force Research Laboratory, Dayton, Ohio, United States
Show AbstractQuantum information applications require stable, room temperature single photon emitters. Diamond stands out as a host material in its ability to host hundreds of color centers, the most studied of which are the NV and NE8 centers. The NE8 center, in particular, is unique in the ability to generate single photons at a wavelength of 793 nm, but emission near 1550 nm is preferable for integration into existing telecommunications networks. In search of such an emitter, we use an ab initio self-consistent field cluster approach combined with time-dependent density functional theory to sample the first row of transition metals as color centers in diamond. The results of defect structure studies, thermodynamic stability, and emission characteristics are presented.
9:00 PM - ED1.7.05
Reliable Industrial Optical Metrology for Characterization of Stress, Dimensions, and Electrical Properties Silicon Carbide (SiC) Epilayers Grown on SiC and Other Isotropic, and Anisotropic Substrates
Wojciech Walecki 1 , Jae Ryu 1 , Nikos Jaeger 1
1 , Frontier Semiconductor, San Jose, California, United States
Show AbstractWe present metrologies developed for conventional silicon applications as adopted for SiC epilayers characterization. In particular we discuss information which can be learned from use of low coherence interferometry [1], optical lever stress metrology [2], Raman spectroscopy [3], contact and noncontact resistivity [4, 5], and epi layer reflectometry. We discuss range, accuracy and fundamental physics limitations of each of these techniques, in context of SiC characterization. We illustrate our presentation with practical industrial examples ranging from power electronics to light emission devices manufacturing.
We focus our attention on characterization of SiC bulk and epilayer interface. We discuss doping level may affect these types of measurements, and provide practical limits for such measurements.
We compare use of these standard techniques on Si and SiC material and we discuss challenges specific to SiC.
[1] Walecki, Wojciech, et al. "Non-contact fast wafer metrology for ultra-thin patterned wafers mounted on grinding and dicing tapes." Electronics Manufacturing Technology Symposium, 2004. IEEE/CPMT/SEMI 29th International. IEEE, 2004.
[2] Brongersma, S. H., et al. "Grain growth, stress, and impurities in electroplated copper." Journal of materials research 17.03 (2002): 582-589.
[3] Walecki, Wojciech J., et al. "Novel combined low-coherence interferometry spectrally resolved reflectometry compatible with high-resolution Raman spectroscopy for nondestructive characterization of MEMS structures."MOEMS-MEMS 2006 Micro and Nanofabrication. International Society for Optics and Photonics, 2006.
[4] Faifer, V. N., et al. "Influence of halo implant on leakage current and sheet resistance of ultrashallow p-n junctions." Journal of Vacuum Science & Technology B 25.5 (2007): 1588-1592.
[5] Clarysse, Trudo H., et al. "Accurate sheet resistance measurement on ultra-shallow profiles." MRS Proceedings. Vol. 912. Cambridge University Press, 2006.
9:00 PM - ED1.7.06
Boron Doping of HFCVD Grown Diamond for Device Applications
Gary Harris 1 2 , Amber Wingfield 1 2 , J Griffin 2 1
1 Electrical and Computer Engineering, Howard University, Washington, District of Columbia, United States, 2 Howard Nanoscale Science & Engineering Facility, Howard University, Washington, District of Columbia, United States
Show AbstractIn this work, we report on the boron doping of diamond using at solid boron oxide source. The boron source was place in closed proximity to the substrate in a hot-filament chemical vapor deposition reactor. The distance for the hot-filament tungsten wire source was varied as well as the methane (CH4) concentration. The doping concentration varied over a wide range with concentrations as high as 1019 cm-3. The Raman spectra and XRD measurements indicate the presence on boron in the as grown epi-layers in both single crystalline and polycrystalline films grown on SiC and Si substrates. SIMS data tracks the 11 B and 12C profiles. After growth, metal contacts of titanium (300Å) and then gold (1500Å) on top of the Ti are deposited by e-beam evaporation. These samples were used to obtain Hall measurements from the as grown samples. The measurements revealed at Hall mobility in the 75-50 cm2/v-sec and a doping of 1-3 x 1019 cm-3. The color of as grown samples was blue; typically see for boron-doped diamond. This work was supported by the STC Center for Integrated Quantum Materials, NSF Grant No. DMR-1231319.
9:00 PM - ED1.7.07
A Comparison of NV Centers in Diamond and 3C-SiC—A Photo EPR Study
Hans Jurgen von Bardeleben 1 , Jean Louis Cantin 1 , Eva Rauls 2 , Uwe Gerstmann 2
1 , University Pierre et Marie Curie, Paris France, 2 Physik, University Paderborn, Paderborn Germany
Show AbstractWhereas the NV center in diamond has been studied for more than two decades the counterpart in 3C-SiC has been assessed only recently [1]. The interest for NV centers in diamond is related to its exceptional magneto-optical properties which have given rise to multiple applications as qubits for quantum computing or nanoscale magnetometry.
It has been suggested by different authors [2-6] that a center with similar properties but in a high-tec semiconductor material would be of maybe even greater interest and the case of NV centers in 3C-SiC has been put forward. In SiC the equivalent of the NV center in diamond is the silicon vacancy nitrogen (VSi-NC) nearest neighbor pair. Defect. As nitrogen in SiC occupies exclusively carbon lattice sites, the other NV center, a carbon vacancy–nitrogen (VC-NSi) nearest neigbor pair has not been considered.
The NV center of interest in this context is the one in the 1- charge state which has spin S=1 ground and excited states. As NV centers are deep centers their charge state in wide bandgap materials will depend on the Fermilevel position which has to be engineered.
We have very recently reported the observation of NV centers in 3C-SiC and assessed their basic properties by Photo EPR spectroscopy. The assignment of this defect has been based on the excellent agreement betwen the experimentally observed and calculated spin Hamiltonian parameters [1].
We will focus in this presentation on the similarities and the strong differences of NV centers in diamond and 3C-SiC which are related to the different material properties. We will further put in perspective the high potantial of NV centers in 3C-SiC which can be easily introduced in Si/3C-SiC epitaxial heterostructures.
1. H.J. von Bardeleben et al
NV Centers in 3C, 4H and 6H Silicon Carbide:
A variable platform for solid state qubits and nanosensors
Phys.Rev.B 94,121202 (2016)
2. J.R.Weber et al,
Quantum computing with defects
J. Appl. Phys.109, 102417(2011)
3. D.DiVincenzo,
Better than excellent
Nature Materials 9, 468 (2010)
4. A.Dzurak,
Quantum computing: diamond and silicon converge
Nature 479, 47 (2011)
5. Alberto Boretti,
Optical materials: silicon carbide's quantum aspects
Nature Photonics 8, 88 (2014)
6. U.Gerstmann et al
Formation and annealing of nitrogen complexes in 3C-SiC
Phys.Rev.B67, 205202 (2003)
9:00 PM - ED1.7.08
Magnetic and Optical Properties of NV Centers in 4H-SiC
Hans Jurgen von Bardeleben 1 , Jean Louis Cantin 1 , Yu Zhou 2 , Weibo Gao 2
1 , University Pierre et Marie Curie, Paris France, 2 , Nanyang Technological University, Singapore Singapore
Show AbstractThe basic magnetic and optical properties of negatively charged (VSi-NC) centers in SiC, the so-called NV centers, have recently been reported [1-3]. Just like their counterpart, the NV center in diamond, they possess spin S=1 ground and excited states, sharp photoluminescence zero phonon lines and optically induced spin polarization of their groundstate. Different from the case of NV centers in diamond, for which the ZPL emission is in the visible, the optical properties of NV centers in SiC are shifted into the near infrared spectral region.
Due to the lower symmetry crystal structure of 4H-SiC as compared to diamond in 4H-SiC four different type of NV centers can occur and have indeed been observed: in 4H –SiC we have two non equivalent lattice sites, which are called quasicubic (k) and hexagonal (h). Depending on the site of the Nitrogen nearest neighbor atom next to the silicon vacancy we have so called axial NV centers (kk, hh) or basal NV centers (hk, kh), i.e. four different types of NV centers. Their basic properties are similar but distinguishable as concerns their spin Hamiltonian parameters and their ZPL emission lines.
In this presentation we will report recent results of CW EPR, pulsed EPR and optically detected magnetic resonance (ODMR) studies of the four different NV centers in 4H-SiC.
1. H.J. von Bardeleben et al
Identification and magneto-optical properties of the NV center in 4H-SiC
Phys.Rev.B92, 064104 (2015)
2. S.A. Zargaleh et al
Evidence for near infrared photoluminescence of nitrogen vacancy centers in 4H-SiC
Phys.Rev.B94, 060102(R)(2016)
3. H.J. von Bardeleben et al
NV Centers in 3C, 4H and 6H Silicon carbide: A variable platform for solid state qubits and nanosensors
Phys.Rev.B94, 121202 (2016)
9:00 PM - ED1.7.09
Directed Covalent Assembly of Nanodiamonds into Continuous Thin Films for MEMS/NEMS
Hongyu Xie 1 , Arden Moore 1 , Adarsh Radadia 1
1 Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana, United States
Show AbstractPolycrystalline diamond thin films have gained significant interest for engineering applications within the last two decades due to a broad range of potential applications, including tribology, unique surface chemistry, biocompatibility, compatibility with silicon microfabrication processes, wide electrochemical potential window, and wide range of tunable electrical and thermal conductivity. The most common and researched methods for fabricating polycrystalline diamond thin films are chemical vapor deposition, microwave, and hot filament, which are expensive and limited to silicon and quartz. Nanodiamonds (NDs) on the contrary posses chemical and physical properties similar to those of diamond, but can be commercially produced with lower cost such as detonation synthesis. This talk will show the feasibility of directed covalent assembly of NDs (35-60 nm clusters) in a layer-by-layer fashion into a continuous film. The success of this project helps overcome the cost and substrate limitations of chemical vapor deposition process for diamond thin films. X-ray photoelectron spectroscopy shows the formation of hypothesized covalent bonds during the film formation. The SEM images of ND films with different cycles show improvement in surface coverage with increasing number of deposition cycles. The ND films produced using 5 deposition cycles and above showed continuous films. We find that small changes in the pH and ionic strength drastically effect the NDs agglomerate size and zeta potential. Hence a good control over solution pH and ionic strength is important for good quality and repeatability. Further, the NDs that were not tethered to surfaces can be re-used upon regeneration. The results obtained here will have far reaching implications in the field of optical coatings, corrosion protection, biosensing, microelectromechanical systems and biomedical implants. Further such directed assembly into heirarchical 3D structures achieved with electrically conductive NDs or fluorescently labeled NDs will allow realization of nanostructures for electronics and photonics applications.
9:00 PM - ED1.7.10
Electronic Structure of TM-V Complexes in Diamond—A Density Functional Theory Analysis
Kamil Czelej 1 , Piotr Spiewak 1 , Krzysztof Kurzydlowski 1
1 , Warsaw University of Technology, Warsaw Poland
Show AbstractDiamond offers a defect centers that could possibly act as quantum bits in quantum information processing at room temperature. Specifically, the nitrogen-vacancy (NV) and the silicon-vacancy (SiV) complexes have been vastly investigated both, theoretically and experimentally. The transition metal-vacancy (TM-V) complexes in diamond may be another interesting candidates in various quantum information processing applications, due to their unique electronic structure, nonzero spin ground state and possible optical excitations. However, relatively small amount of information about these complexes have been reported so far. To fill the gap we carried out a systematic study of selected TM-V centers in diamond using spin-polarized, hybrid density functional theory approach. The revised Heyd-Scuseria-Ernzerhof screened hybrid functional (HSE06) was applied for the total energy calculation. For each defect the equilibrium geometry, formation energy as a function of charge state, excitation energy, nett spin and defect charge transition levels were determined. On the basis of formation energy vs Fermi level diagrams, relative stability of different charge states were predicted. The group theory analysis together with the calculated K-S singe particle energies were used to describe the defect states for neutral TM-V complexes. Finally possible excitations of the defects analysed were determined and subsequently discussed in terms of their usefulness as a color centers. Our theoretical results provide a valuable information on TM-V complexes and may be useful in identification of unknown TM-related centers in diamond from the experimental data.
Symposium Organizers
D. Kurt Gaskill, U.S. Naval Research Laboratory
Adam Gali, Hungarian Academy of Sciences
Brenda VanMil, U.S. Army Research Laboratory
Joerg Wrachtrup, University of Stuttgart
Symposium Support
U.S. Army Research Laboratory-Army Quantum Science and Engineering Program
ED1.8/ED12.8: Joint Session VII: Qubit Arrays and Spin Device Principles
Session Chairs
Fedor Jelezko
Milos Nesladek
Thursday AM, April 20, 2017
PCC North, 100 Level, Room 132 A
9:00 AM - *ED1.8.01/ED12.8.01
Scaled Control of Solid-State Qubit Arrays
Michael Trupke 1
1 , University of Vienna, Vienna Austria
Show AbstractDefects in semiconductors such as silicon, diamond and silicon carbide are promising candidates for the implementation of quantum bits (qubits) and sensors given their long spin coherence lifetimes. Many of the envisaged applications will require control over a large number of sites, and quantum computing in particular will require exquisite control over millions of qubits. However, controlling large numbers of tightly packed defects is a daunting task as access for control lines needs to be provided, and cross-talk can be deleterious.
Here we present a method for the efficient control of large-scale qubit registers, based on quantum interference, which mitigates both of these challenges. The number of controlled sites increases quadratically with the number of control lines, and the method provides precise local, multi-site or global control. The principle is demonstrated experimentally using microfabricated control structures on a diamond chip to manipulate nitrogen-vacancy centres.
Factors affecting site separation, control errors and control speed will be discussed, together with methods to increase the surface density of controlled sites using multi-line pulse sequences. With these methods, the presented control architecture shows promise for simplifying the development of applications in large-scale quantum technology.
9:30 AM - *ED1.8.02/ED12.8.02
Quantum Sensing and Imaging using Color Centers in Diamond and Extensions to Quantum Networks
Dirk Englund 1 , Christopher Foy 1 , Danielle Braje 2 , Hannah Clevenson 1 , Matthew Trusheim 1 , Sinan Karaveli 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 , Massachusetts Institution of Technology Lincoln Laboratory, Lexington, Massachusetts, United States
Show AbstractRecent years have seen tremendous progress in developing a new range of quantum-enhanced sensors based on electronic and nuclear spins in solids, especially using color centers in the wide-bandgap semiconductors diamond and silicon carbide. Here, we describe recent progress in several areas of sensing and imaging using nitrogen vacancy (NV) centers in diamond. 1. Using diamond nanocrystals constaining NV centers, we have developed techniques for wide-field imaging of electrical current distributions and temperature with sub-wavelength resolution and at high speed, with applications in microelectronics chip verification and detection of failure processes in high-power electronics. 2. Fluorescent nanodiamonds are also promising for wide-field imaging of electrical activity in the brain; in particular, we will discuss the behavior of NV-nanodiamonds in electric fields produced inside electrochemical junctions, and the targeted delivery to neuronal cell membranes. 3. We will discuss wide-field nanoscale imaging of strain in polycrystalline diamonds, which also reveals ordered NV orientations in specific crystal domains. 4. Finally, we discuss possible extensions of quantum sensing techniques to quantum networks.
10:00 AM - *ED1.8.03/ED12.8.03
Silicon Carbide—Material Growth and Defect Engineering for Spintronics
Nguyen Son 1 , Jawad Ul Hassan 1 , Pontus Stenberg 1 , Ian Booker 1 , Ivan Ivanov 1 , Olof Kordina 1 , Matthias Widmann 2 3 , Matthias Niethammer 2 3 , Sang-Yun Lee 2 4 , Takeshi Ohshima 6 , Joerg Wrachtrup 2 3 5 , Erik Janzen 1
1 , Linkoping University, Linkoping Sweden, 2 , University of Stuttgart, Stuttgart Germany, 3 , Stuttgart Research Center of Photonic Engineering (SCoPE) and IQST, Stuttgart Germany, 4 , Korea Institute of Science and Technology, Gyeonggi-do Korea (the Republic of), 6 , National Institutes for Quantum and Radiological Science and Technology, Takasaki Japan, 5 , Max Planck Institute for Solid State Research, Stuttgart Germany
Show AbstractSilicon carbide (SiC) has recently been shown to host intrinsic defects and impurities, which have optical and spin properties suitable for room-temperature applications in quantum information technology and sensing. Realization of single defects that work as single spin sources with long spin coherence times requires ultra-pure materials to start with. We will show results from our chemical vapor deposition (CVD) growth of thick, ultra-pure epitaxial layers for single defect studies. For further improvement of the spin coherence time, the reduction of the spin bath of the host material, i.e. the nuclear spins of 29Si (I=1/2, 4.7 % natural abundance) and 13C (I=1/2, 1.1%), is desired. We will show results from our CVD growth of thick enriched zero-nuclear-spin 28Si12C layers (99.85 % of 28Si and 99.98 % of 12C) with the residual effective n-type doping in the range of ~1×1013 cm–3. For defect engineering, electron irradiation is used to create intrinsic defects, e.g. the Si vacancies and divacancies, in SiC with well-controlled concentrations for single defect and ensemble studies. Doping with transition metals will be presented with focusing on V-doping using metalorganic precursor gas during CVD growth. Results on growth of different p-i-n structures for vertical and in-plane diodes and realization of single defects in the devices will be presented.
10:30 AM - ED1.8.04/ED12.8.04
Defects and Decoherence at Diamond Surfaces
Alastair Stacey 1 2 , Jyh-Pin Chou 3 , Nathalie de Leon 5 , Anton Tadich 7 , Chris Pakes 6 , Liam Hall 8 , Jean-Philippe Tetienne 1 , Adam Gali 3 4 , Lloyd Hollenberg 1 8
1 Centre for Quantum Computing and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria, Australia, 2 , Melbourne Centre for Nanofabrication, Melbourne, Victoria, Australia, 3 Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest Hungary, 5 Electrical Engineering, Princeton University, Princeton, New Jersey, United States, 7 , Australian Synchrotron, Clayton, Victoria, Australia, 6 Department of Physics, LaTrobe University, Melbourne, Victoria, Australia, 8 School of Physics, University of Melbourne, Melbourne, Victoria, Australia, 4 Department of Atomic Physics, Budapest University of Technology and Economics, Budapest Hungary
Show AbstractHere we present detailed synchrotron investigations of tailored diamond surfaces, in conjunction with near-surface qubit metrology of these surfaces. We have thus identified new, unexpected, crystalline defects at the material surface and enabled a greater understanding of the primary causes of decoherence and qubit population instabilities in near-surface engineered devices.
Defect centres (qubits) in diamond are amongst the vanguard of the nascent quantum technologies revolution, driving advances in quantum computing and sensing applications.1,2 As these technologies begin to be applied in real devices, these optically active defects are being increasingly located within nanometres of the diamond surface,3 where their quantum properties such as coherence time and spectral width are reported to experience significant degradation,4 compared to their bulk properties. There have been recent advances in theoretical proposals for ideal diamond surface chemistries,5 which link unoccupied electronic surfaces states with degraded photophysical properties. To date experimental achievements have included the introduction of novel surface terminations,6 and process optimization efforts, yielding significant improvements in near-surface defect coherence values.7 Despite these efforts, surface noise and defect instability near surfaces remains a significant challenge for any quantum application and are a major hurdle for realization of real-world devices.
We will provide experimental evidence of unexpected crystalline defects at the diamond surface, as well as theoretical calculations showing that these defects produce low-lying trap states in the near-surface region, inhibiting the charge population and stability of near-surface NV centres. We will detail experimental treatment methods for the removal of these surface defects and show measurement evidence of their effects on NV centres at various depths. We will also detail new correlations between surface contaminants and decoherence of these defects.
1 Rondin, L. et al. Magnetometry with nitrogen-vacancy defects in diamond. Rep. Prog. Phys. 77, 056503 (2014).
2 Schirhagl, R., Chang, K., Loretz, M. & Degen, C. L. Nitrogen-Vacancy Centers in Diamond: Nanoscale Sensors for Physics and Biology. Annu. Rev. Phys. Chem. 65, 83-105, (2014).
3 Rosskopf, T. et al. Investigation of Surface Magnetic Noise by Shallow Spins in Diamond. Phys. Rev. Lett. 112, 147602 (2014).
4 Wrachtrup, J., Jelezko, F., Grotz, B. & McGuinness, L. Nitrogen-vacancy centers close to surfaces. MRS Bulletin 38, 149-154, (2013).
5 Kaviani, M. et al. Proper Surface Termination for Luminescent Near-Surface NV Centers in Diamond. Nano Lett. 14, 4772-4777,(2014).
6 Stacey, A. et al. Nitrogen Terminated Diamond. Advanced Materials Interfaces 2 (2015).
7 Lovchinsky, I. et al. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic. Science, (2016).
10:45 AM - ED1.8.05/ED12.8.05
High Purity and High Quality Homoepitaxial Diamond Growth for Quantum Information and Quantum Sensing Device Applications
Tokuyuki Teraji 1 , Philipp Neumann 2 , Joerg Wrachtrup 2 , Lachlan Rogers 3 , Fedor Jelezko 3 , Junichi Isoya 4
1 , National Institute for Materials Science, Tsukuba Japan, 2 , University of Stuttgart, Stuttgart Germany, 3 , Ulm University, Ulm Germany, 4 , University of Tsukuba, Tsukuba Japan
Show AbstractWith quantum information and quantum sensing devices of the next generation in mind, we provide a guideline for the growth of homoepitaxial diamond films that possess higher crystalline quality, higher chemical purity, and a higher carbon isotopic ratio. A custom-built microwave plasma-assisted chemical vapor deposition system was constructed to achieve these requirements. To improve both the purity and crystalline quality of homoepitaxial diamond films, an advanced growth condition was applied: higher oxygen concentration in the growth ambient. Under this growth condition for high-quality diamond, a thick diamond film of >30 µm was deposited reproducibly while maintaining high purity and a flat surface [1]. Then, combining this advanced growth condition for non-doped diamond (100) and (111) film with a unique doping technique that provides parts-per-billion order doping, single-color centers of either nitrogen-vacancy or silicon-vacancy centers that show excellent properties were formed [2, 3]. These advanced growth techniques are expected to accelerate the research fields of quantum information and quantum sensing devices using diamond.
[1] T. Teraji, J. Appl. Phys. 118, 115304 (2015).
[2] J. Michl, T. Teraji, S. Zaiser, I. Jakobi, G. Waldherr, F. Dolde, P. Neumann, M. W. Doherty, N. B. Manson, J. Isoya, J. Wrachtrup, App. Phys. Lett. 104, 102407 (2014).
[3] L.J. Rogers, K.D. Jahnke, T. Teraji, L. Marseglia, C. Müller, B. Naydenov, H. Schauffert, C. Kranz, J. Isoya, L.P. McGuinness and F. Jelezko, Nature Communications, 5, 4739 (2014).
11:00 AM - ED1.8/ED12.8
BREAK
ED1.9: Near-Infrared Emitters for Quantum Technology
Session Chairs
Igor Aharonovich
D. Kurt Gaskill
Thursday PM, April 20, 2017
PCC North, 100 Level, Room 128 B
11:30 AM - *ED1.9.01
NV Centers in Silicon Carbide—From Theoretical Predictions to Experimental Observation
Hans Jurgen von Bardeleben 1 , Jean Louis Cantin 1 , Andras Csore 3 , Adam Gali 4 , Eva Rauls 2 , Uwe Gerstmann 2
1 , University Pierre et Marie Curie, Paris France, 3 , Budapest University of Technology, Budapest Hungary, 4 Wigner Research Center for Physics, Hungarian Academy of Science, Budapest Hungary, 2 Physik, University Paderborn, Paderborn Germany
Show AbstractThe NV center in diamond has become the object of intense studies in the last decade due to its exceptional magneto-optical properties which have given rise to multiple applications as qubits for quantum computing or nanoscale magnetometry. Following this, different authors have predicted [1-4] that NV centers should exist also in silicon carbide and have equally properties which should allow their application as qubits for quantum computing and nanometric sensors.
We have recently reported [5,6] the observation of NV centers in 4H-SiC and very recently assessed their basic properties in all three polytypes 3C, 4H, 6H [7]. The results obtained by electron paramagnetic resonance spectroscopy, photoluminescence, optically detected magnetic resonance and calculations of their electronic structure by ab initio calculations confirm the initial predictions and show the rich potential of these defects which similar but modified properties as compared to the NV center in diamond.
Whereas in diamond only one NV center exists with four different [111] orientations, the situation in SiC is more complex : N in SiC ocupies only carbon lattice sites and 4H and 6H polytypes have a lower hexagonal symmetry giving rise to inequivalent quasicubic and hexagonal cation lattice sites: thus we would expect and have assessed one NV center in 3C, four distinct NV centers in 4H and six NV centers in 6H polytypes.
A further difference to the case of diamond is the change of the spectral region of the photoluminescence zero phonon lines associated with each NV center: they are shifted from the red (632nm) in diamond to the near infrared region (1200nm…1400nm) in SiC. Optical induced spin polarization of the groundstate allowing initializiation and read out of the spin configuration have been observed. First results on the spin coherence times show encourageing values in the microsecond range which might be further improved by single defect spectroscopy in isotopically modified SiC layers.
We will present an overview of the principal properties of these centers and report new results obtained by time resolved ODMR spectroscopy.
1. J.R.Weber et al,
Quantum computing with defects
J.of Appl.Phys.109, 102417(2011)
2. D.DiVincenzo,
Better than excellent
Nature Materials 9, 468 (2010)
3. A.Dzurak,
Quantum computing: diamond and silicon converge
Nature 479, 47 (2011)
4. Alberto Boretti,
Optical materials: silicon carbide's quantum aspects
Nature Photonics 8, 88 (2014)
5. H.J.von Bardeleben et al
Identification and magneto-optical properties of the NV center in 4H-SiC
Phys.Rev.B92, 064104 (2015)
6. S.A.Zargaleh et al
Evidence for near infrared photoluminescence of nitrogen vacancy centers in 4H-SiC
Phys.Rev.B94, 060102(R)(2016)
7. H.J.von Bardeleben et al
NV Centers in 3C, 4H and 6H Silicon carbide:
A variable platform for solid state qubits and nanosensors
Phys.Rev.B 94,121202 (2016)
12:00 PM - *ED1.9.02
New Color Centers in Diamond for Long Distance Quantum Communication
Nathalie de Leon 1
1 , Princeton University, Princeton, New Jersey, United States
Show AbstractColor centers in diamond are a promising platform for quantum communication, as they can serve as solid state quantum memories with efficient optical transitions. Much recent attention has focused on the negatively charged NV center in diamond, which has a spin triplet ground state electronic configuration that can be measured and initialized optically, exhibits long spin coherence times at room temperature, and has narrow, spin-conserving optical transitions. However, the NV center exhibits a large static and dynamic inhomogeneous linewidth, and over 97% of its emission is in a broad, incoherent phonon side band, severely limiting scalability. Alternatively, the negatively charged SiV center exhibits excellent optical properties, with 70% of its emission in the zero phonon line and a narrow inhomogeneous linewidth. However, SiV- suffers from short electron spin coherence times, limited by an orbital relaxation rate (T1) of around 40 ns at 5 K.
Informed by the limitations of NV- and SiV-, we have developed new methods to control the diamond Fermi level in order to stabilize the neutral charge state of SiV, thus accessing a new spin configuration. SiV0 exhibits a T1 exceeding one minute at 4 K, and >90% of its emission is in its zero phonon line. These properties make it a promising candidate for applications in long distance quantum communication.
12:30 PM - *ED1.9.03
Single Color Center Engineering in Nanodiamond
Maneesh Gupta 1 , Nicholas Gothard 2 , Jennifer Wohlwend 1 , Jonghoon Lee 1 , Piyush Shah 1 , Michael Check 1 , Douglas Dudis 1 , Luke Bissell 1
1 , Air Force Research Laboratory, WPAFB, Ohio, United States, 2 Department of Chemistry and Physics, Bob Jones University, Greenville, South Carolina, United States
Show Abstract
A diamond color center works as a nearly ideal single-photon source (SPS), having high emission rates at room temperature, and excellent photostability. We will fabricate diamond color centers at precise locations that can be harnessed as a robust, room-temperature SPS for quantum information applications. A challenge to implementing diamond SPSs is the precise incorporation of a single color center in the crystal lattice. A bottom-up approach could be advantageous compared to top-down strategies by offering higher efficiency and robust control. We are developing molecular seed clusters capable of: 1) efficiently nucleating diamond nanocrystals, and 2) precise incorporation of single nitrogen atoms in single nanocrystals. We are accomplishing this by exploring seed-induced nucleation in a microwave plasma chemical vapor deposition reactor. The wide range of functional groups that can be attached to seed clusters could provide a chemical means to incorporate single defects into nanodiamond. We will present the characterization of diamond nanoparticles with sizes of 5 – 50 nm and discuss the efficacy of incorporating nitrogen-vacancy centers via nucleation on nitrogen-functionalized molecular seed clusters. Our seed-induced nucleation approach can also controllably synthesize many other color centers that have infrared emission. An infrared SPS will allow device implementation in current telecom and free-space channels. To gain insight on new defects in diamond that could yield emission in the telecom band, we have studied transition metal atoms dopants in the diamond lattice via the GAMESS (General Atomic Molecular and Electronic Structure System) cluster calculation package. In particular, time-dependent density functional theory calculations of the excitation energy predicts that a vanadium-nitrogen related defect emits at ~ 0.9 eV.
ED1.10: Simulation and Fabrication of Defect Spins
Session Chairs
Sang-Yun Lee
Rachael Myers-Ward
Thursday PM, April 20, 2017
PCC North, 100 Level, Room 128 B
2:30 PM - *ED1.10.01
Spin Coherence and Optical Properties of the Silicon Vacancy in SiC
Samuel Carter 1 , Oney Soykal 1 , Pratibha Dev 3 , Sophia Economou 4 , Bradley Weaver 1 , Peter Brereton 2 , Evan Glaser 1 , Karl Hobart 1 , Fritz Kub 1 , Alexander Giles 5 , Joshua Caldwell 1 , Rachael Myers-Ward 1 , D. Kurt Gaskill 1
1 , U.S. Naval Research Laboratory, Washington, District of Columbia, United States, 3 Department of Physics and Astronomy, Howard University, Washington, District of Columbia, United States, 4 Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States, 2 Physics Department, U.S. Naval Academy, Annapolis, Maryland, United States, 5 , NRC Postdoc at the U.S. Naval Research Laboratory, Washington, District of Columbia, United States
Show AbstractThe silicon vacancy in silicon carbide is currently a promising candidate for applications in quantum information and quantum sensing. A number of studies have now demonstrated room temperature optically induced spin polarization and readout in this system and have measured spin coherence properties. These properties, combined with the mature device fabrication and wafer-scale growth of SiC, should enable a robust solid state platform for quantum information. Nevertheless, there are still many challenges to understanding and improving the spin coherence and optical properties of the silicon vacancy, such as integrating the defect in a resonant cavity that has an efficient interface with photons. We will present recent efforts to improve our understanding of both the spin coherence properties and the low temperature optical properties of the Si vacancy in 4H-SiC. Room temperature optically detected magnetic resonance and spin echo measurements have been performed as a function of magnetic field that reveal some of the unique features that occur in this spin 3/2 system. In particular, there is strong spin echo modulation at low magnetic fields that in an ensemble lead to strong damping of the echo. The complex modulation is well described by a theoretical model that takes into account the many possible locations of nearby 29Si and 13C nuclei. We will also present work on characterizing the low temperature optical properties of Si vacancies, including the linewidth of the zero-phonon-line, as well as work on integrating these defects in optical structures to enhance emission properties.
3:00 PM - ED1.10.02
Multiscale Green’s Function Method for Modeling Strain Field Due to a Nitrogen-Vacancy Center in Diamond
Vinod Tewary 1 , Edward Garboczi 1
1 , National Institute of Standards and Technology, Boulder, Colorado, United States
Show AbstractQuantum computers represent the next ‘quantum’ jump in the efficiency of computers and other data processing devices. One of the most important issues in the design of quantum computers is the choice of suitable materials. An individual N-V (nitrogen – vacancy) center in diamond or nano-diamond is a possible qubit or a basic unit of a quantum computer. It has potential applications in other solid state devices and is quite stable even in nanodiamonds. Study of the N-V center in diamond, both synthetic and natural, is, therefore, of great topical interest.
An N-V center is essentially a lattice defect. It consists of a substitutional nitrogen impurity with a nearest neighbor vacancy in the diamond lattice. A lattice defect represents a break in the translation symmetry of the lattice. Consequently, it causes a distortion or strain in the lattice, which also distorts the electronic wave functions and perturbs the associated energy levels. This would affect the efficiency as well as the reliability of the electronic device. This effect is likely to be a serious material issue for quantum computers because such a strain can result in decoherence of the qubits and hence degradation of the quantum device. It is, therefore, of paramount importance to develop modeling and measurement techniques of the local strain field around an N-V center in diamond.
Modeling the strain field due to a point defect in a lattice is a multiscale problem, because the response of the lattice near a point defect must be represented by using its discrete atomistic structure due to the known limitations of the continuum model. On the other hand, the strain field, measured far away from the defect, is essentially a continuum parameter, which is defined in terms of the derivative of the displacement field. It is, therefore, necessary to use a multiscale model that can link the nanometer scale of the discrete lattice to macroscales of the continuum model over which the strains are measured.
We will describe a multiscale Green’s function method for modeling an N-V center in diamond. The model is computationally efficient and can simulate a million atoms on an ordinary desktop computer. It can account for free surfaces and interfaces in the material and their elastic interaction with the N-V center. Numerical results will be presented for the strain field due to an N-V center in diamond assuming a simple but realistic interatomic potential. The chosen potential reproduces the phonon frequency spectrum and the elastic constants of the host diamond lattice reasonably well. The importance of the strain field and materials characterization of the quantum devices will be briefly discussed.
3:15 PM - ED1.10.03
Defects in SiC Characterized by Magnetometry
Shengqiang Zhou 1
1 , Helmholtz-Zentrum Dresden-Rossendorf, Dresden Germany
Show AbstractSilicon carbide (SiC) is a wide band-gap semiconductor with unique mechanical, electrical, and thermal properties, which make the material suitable for many demanding applications in extreme conditions, such as high temperature, high power, high frequency and high radiation exposure. The spin states related with defects in SiC can be optically addressed and coherently controlled up to room temperature [1] or can be ferromagnetically coupled [2, 3], opening the door for semiconductor spintronics and quantum computing.
In this contribution, we present a comprehensive investigation on defects in SiC by using magnetometry [2-6]. In combination with X-ray absorption spectroscopy, high-resolution transmission electron microscopy and first-principles calculations, we try to understand the mechanism of defect induced magnetism in SiC in a microscopic picture.
For neon or xenon ion implanted SiC, we identify a multi-magnetic-phase nature [3, 4]. The magnetization of SiC can be decomposed into paramagnetic, superparamagnetic and ferromagnetic contributions. The ferromagnetic contribution persists well above room temperature and exhibits a pronounced magnetic anisotropy. By combining X-ray magnetic circular dichroism and first-principles calculations, we clarify that p-electrons of the nearest-neighbor carbon atoms around divacancies are mainly responsible for the long-range ferromagnetic coupling [5]. Thus, we provide a correlation between the collective magnetic phenomena and the specific electrons/orbitals.
For neutron irradiated SiC, we observe a strong paramagnetism, scaling up with the neutron fluence [6]. A weak ferromagnetic contribution only occurs in a narrow fluence window or after annealing. The interaction between the nuclear spin and the paramagnetic defect can effectively tune the spin-lattice relaxation time (T1) as well as the nuclear spin coherent time (T2). For the sample with the largest neutron irradiation fluence, T1 and T2 are determined to be around 520 s and 1 ms at 2K, respectively.
[1] W. Koehl, et al., Nature 479, 84 (2011).
[2] Y. Liu, et al., Phys. Rev. Lett. 106, 087205 (2011).
[3] L. Li, et al., Appl. Phys. Lett. 98, 222508 (2011).
[4] Y. Wang, et al., Phys. Rev. B 89, 014417 (2014).
[5] Y. Wang, et al., Scientific Reports, 5, 8999 (2015).
[6] Y. Wang, et al., Phys. Rev. B 92, 174409 (2015).
3:30 PM - ED1.10.04
Investigation of the Structural and Optical Behaviors of Self-Aligned Erbium-Doped Silicon-Carbide Nanowires towards Quantum Technologies
Vasileios Nikas 1 , Natasha Tabassum 1 , Brian Ford 1 , Edward Crawford 2 , Spyros Gallis 1
1 , State University of New York Polytechnic Institute, Albany, New York, United States, 2 , GLOBALFOUNDRIES, Fishkill, New York, United States
Show AbstractDesigning high-functional silicon-based nanosystems and the precise placement of single emitters are critical building blocks towards the practical development of quantum technologies. Herein, we report pertinent results pertaining to the study of material behaviors of ultrathin (e.g. diameter, d < 20 nm) erbium (Er3+)-doped silicon carbide (SiC:Er) nanowire (NW) arrays. The polycrystalline SiC NWs were grown in a self-aligned manner through a novel catalyst-free chemical-vapor-deposition (CVD) synthesis route. A key enabler of this synthesis route is that the SiC NWs are engineered with tailored geometry in precise locations during nanofabrication. This is translated to an on-demand placement and tailoring of photo-stable photon emitters (Er3+) from single isolated to ensemble ions in the technologically-friendly SiC NWs. The growth, dimensionality and Er3+ doping effects on the structure, optoelectronic properties (e.g. radiative quantum efficiency and NW-related photoluminescence (PL)) of SiC NWs were investigated at extremely small scale, establishing a link between synthesis-structure-property. To this end, their structural and optical characteristics were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopic ellipsometry (UV-VIS-SE) and Raman spectroscopy. The evolution of FTIR absorption spectra with forming-gas annealing temperature revealed a substantial narrowing of the FWHM at 1200 oC, which was accompanied by a change of the FTIR lineshape from Gaussian to Lorentzian, comparable to values for high-quality crystalline SiC. Using a combination of correlation and comparison of PL and PL excitation (PLE) microspectroscopy, time-resolved PL and power/temperature-dependence PL, and UV-VIS-SE analyses, defects and size effects on their light emitting properties and underlying mechanisms for light emission in near-infrared range were explored. An enhancement by ~two orders of magnitude of the room-temperature 1540 nm (telecom-wavelength) PL from photo-stable Er3+ was observed in SiC:Er NW compared to its thin-film counterpart. Additional the Er3+ emission in SiC:Er NW revealed a long radiative lifetime (~3.8 ms) and broadband excitation characteristics with an effective excitation cross-section (σeff) at least ~four orders of magnitude larger (~1×10-16 cm2) than direct Er optical excitation in silicon dioxide control. These results may suggest an efficient energy transfer mechanism from the NW matrix (SiC nanocrystals) to Er3+ ions.
ED1.11: Nanodiamonds for Quantum Technology and Sensing
Session Chairs
Thursday PM, April 20, 2017
PCC North, 100 Level, Room 128 B
4:00 PM - ED1.11.01
Focused Ion Beam Implantation with Single Ion Detection for SiV Center Creation in Diamond
Edward Bielejec 1 , John Abraham 1 , Ryan Camacho 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractRecent publications [A. Sipahigil et al., arXiv:1608.05147, among others] have demonstrated the capability of silicon vacancy centers (SiV) in diamond as a potential platform for solid-state qubits. We report on recent work at Sandia National Laboratories (SNL) using a combination of focused ion beam implantation and single ion detection to explicitly control both the location and number of implanted Silicon ions. These techniques allow for deterministically controlled color center formation using top-down ion implantation.
The focused ion beam implantation is performed using the SNL nanoImplanter (nI). The nI is a 100 kV focused ion beam system combining a <10 nm spot with a mass velocity filter allowing the user to choose the ion species, isotope and energy from a liquid metal alloy ion source (LMAIS). The nI can provide ions from approximately one-third of the periodic table of elements. Using this system we have demonstrated positioning resolution of between <50 nm for ion implantation into nanostructures.
Single ion detection is performed using an in-situ ion beam induced charge (IBIC) technique. We have detected single 200 keV Si ion implantation with a signal-to-noise ratio (SNR) approaching 10 [J. B. S. Abraham et al., Appl. Phys. Lett. 109, 063502 (2016)] This allows us to directly count in the number of implanted Si ions, reducing the uncertainty in the number of resulting SiV centers by beating the Poisson distribution. Furthermore, this provides an excellent technique to characterize sub-surface damage due to both ion implantation and surface preparation steps that may directly impact spin lifetime.
The combination of focused ion beam implantation to control the spatial location and directly counting in the implanted ions has the potential to allow for the creation of deterministically fabricated single SiV centers in diamond nanostructures.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
4:15 PM - *ED1.11.02
Optical Levitation of Nanodiamonds in Vacuum without Heating
Gavin Morley 1
1 , University of Warwick, Coventry United Kingdom
Show AbstractOptical trapping at high vacuum of a nanodiamond containing a nitrogen vacancy centre would provide a test bed for several new phenomena in fundamental physics [1-6]. However, the nanodiamonds used so far have absorbed too much of the trapping light, heating them to destruction (above 800 K) except at pressures above 10 mbar where air molecules dissipate the excess heat [7-10]. Here we show that milling diamond of 1000 times greater purity creates nanodiamonds that do not heat up even when the optical trap intensity is raised above 700 GW/m2 below 5 mbar of pressure. For more details, see A. C. Frangeskou et al., arXiv:1608.04724 (2016). The large quantities of high purity nanodiamonds made in this way may also be useful as nano-scale sensors of magnetic field and temperature.
[1] M. Scala et al., Physical Review Letters 111, 180403 (2013).
[2] C. J. Riedel, Physical Review D 88, 116005 (2013).
[3] Z.-q. Yin, T. Li, X. Zhang and L. M. Duan, Physical Review A 88, 033614 (2013).
[4] A. Albrecht, A. Retzker and M. B. Plenio, Physical Review A 90, 033834 (2014).
[5] C. Wan et al., Physical Review A 93, 043852 (2016).
[6] C. Wan et al., Physical Review Letters 117, 143003 (2016).
[7] A. T. M. A. Rahman et al., Scientific Reports 6, 21633 (2016).
[8] L. P. Neukirch, E. von Haartman, J. M. Rosenholm and A. Nick Vamivakas, Nat Photon 9, 653 (2015).
[9] T. M. Hoang, J. Ahn, J. Bang and T. Li, Nat Commun 7, 12250 (2016).
[10] T. M. Hoang et al., Physical Review Letters 117, 123604 (2016).
4:45 PM - ED1.11.03
Optimizing Structure in Nanocrystalline Diamonds Using In Situ Strain-Sensitive Bragg Coherent Diffraction Imaging
F. Joseph Heremans 1 2 , Stephan Hruszkewycz 1 , Wonsuk Cha 1 , Paolo Andrich 2 , Christopher Anderson 2 , Andrew Ulvestad 1 , Ross Harder 3 , Paul Fuoss 1 , David Awschalom 2 1
1 Materials Sciences Division, Argonne National Laboratory, Argonne, Illinois, United States, 2 Institute for Molecular Engineering, University of Chicago, Chicago, Illinois, United States, 3 X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois, United States
Show AbstractThe nitrogen-vacancy center in diamond has attracted considerable attention for nanoscale sensing due to unique optical and spin properties. Many of these applications require diamond nanoparticles which often contain large amounts of residual strain due to the detonation or milling process used in their fabrication. Here, we present experimental, in-situ observations of changes in morphology and internal strain state of commercial diamond nanocrystals during high-temperature annealing in a flowing helium atmosphere. 3D images were obtained as a function of time and temperature using a new synchrotron based hard x-ray imaging technique. Bragg coherent diffraction imaging (BCDI) reconstructs a strain-sensitive 3D image of individual sub-micron-sized crystals by inverting the diffracted x-ray intensity pattern measured about a Bragg peak of the crystal [1].
We find that structural changes to the diamond nanoparticles are minimal up to 650 C, and that at higher temperatures up to 750 C, nanodiamond crystallites show a reduction in size. Additionally, the degree of internal strain within nanodiamond particles was found to decrease once annealed above 650 C. Raman spectroscopy was used to verify that the decrease in size of the crystalline nanodiamonds is likely due to graphitization of the outer layer [2]. Our findings potentially enable the design of efficient processing of inexpensive commercial nanodiamonds into viable materials suitable for device design.
BCDI reconstructions were supported supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
[1] I. Robinson and R. Harder, Nature Materials 8, 291 (2009).
[2] S. Osswald et al., J. Am. Chem. Soc. 128, 11635 (2006).
5:00 PM - ED1.11.04
Molecular Control of Nanodiamond Doping via a High Temperature, High Pressure Process
Matthew Crane 1 , Peter Pauzauskie 1
1 , University of Washington, Seattle, Washington, United States
Show AbstractNanoscale diamond has attracted widespread interest, due to its wide bandgap, which can support a cornucopia of interesting color centers, isolated from the host’s band structure. A fundamental understanding of the defects within diamond and controllable synthesis methods has led to incredible applications, including optically-initialized quantum bits for computing, high-fidelity sensing, and bright fluorescence. To date, it has been challenging to produce new defects in diamond due to diffusion limitations, which prevent incorporation of atoms larger than carbon, and ion implantation limitations, which produce a range of defects and induce lattice damage.
Here, we demonstrate a new method for the controlled doping of nanodiamond by first doping a nanostructured carbon precursor and then converting it to nanostructured diamond at high temperature, high pressure conditions in a laser-heated diamond anvil cell (DAC). We observe that the molecules doped into the carbon appear as dopants in the diamond product. Specifically, we find that silicon and nitrogen moieties doped into the carbon precursor appear as negatively-charged silicon divacancy (SiV-) and nitrogen vacancy (NV-) centers, which we investigate with scanning transmission x-ray and aberration-corrected scanning transmission electron microscopy. Additionally, we demonstrate that photothermal heating can control the formation of NV- centers at high pressure conditions. We model this process using Mie and CBΩ theories to investigate the mechanisms of diamond growth and NV- formation, identifying that high pressure vacancy diffusion likely controls NV- formation. We conclude with initial observations of creating novel defects in nanodiamond using this methodology.
5:15 PM - ED1.11.05
Measuring Vacancies and Nitrogen-Vacancy Centers in Nanodiamonds Using Electron Energy Loss Spectroscopy in a TEM
Shery Chang 1 , Amanda Barnard 2 , Christian Dwyer 1
1 , Arizona State University, Tempe, Arizona, United States, 2 , Commonwealth Scientific and Industrial Research Organisation (CSIRO), Melbourne, Victoria, Australia
Show AbstractNitrogen-vacancy centers (N-V) in nanocrystalline diamond have been studied extensively for their interesting photolumines- cence properties . Negatively-charged N-V centres (N-V−1) can emit visible light that is readily detectable, even at room temperature. In order to meet the demand required by the applications, efforts have been made to increase the N-V concentration via an increased vacancy concentration, e.g., using high-energy irradiation. However, it is far from clear whether this approach is effective, since the presence of planar and/or line defects and strain may influence the vacancy diffusion. Moreover, controlling and monitoring the production of vacancies is extremely challenging, and no technique currently exists for directly measuring the vacancy concentration in nanocrystalline materials.
Here we demonstrate that it is possible not only to detect, but to quantify, vacancies in nanodiamond using a combined experimental- theoretical approach. The measurement of vacancies is based on high-energy- resolution electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM). Using EELS simulations, we show that vacancies and N-V centers in diamond can be identified by a well-defined peak in the pre-edge of the carbon K- edge spectrum. Then, the probability of forming N-V centers for a given particle size, and nitrogen and vacancy concentrations, is estimated using density functional tight- binding simulations and analytical calculations.
Finally, we explore the new capability of ultra-high energy resolution EELS in a STEM, where 20meV resolution is now possible. This allows us to directly measure the signal from the N-V center in the low-loss regime. The interpretation and possible quantification of this signal will be discussed.
5:30 PM - *ED1.11.06
Quantum Sensing and Imaging with Diamond Spins
Ania Bleszynski Jayich 1 , Alec Jenkins 1 , Amila Ariyaratne 1 , Christopher Reetz 1 , D. Bluvstein 1
1 Physics Department, University of California, Santa Barbara, Santa Barbara, California, United States
Show AbstractThe nitrogen vacancy (NV) center in diamond is an atomic-scale defect in diamond
that is highly sensitive to a wide variety of fields: magnetic, electric, thermal, and
strain. Here I discuss an NV-based imaging platform (Fig. 1) where we have
incorporated an NV center into a scanning probe microscope and used it to image
vortices in superconductors [1] and skyrmions, nanoscale topological spin textures, in
thin film magnetic multilayers. A grand challenge to improving the spatial resolution
and magnetic sensitivity of the NV is mitigating surface-induced quantum
decoherence, which I will discuss in the second part of this talk. Decoherence at
interfaces is a universal problem that affects many quantum technologies, but the
microscopic origins are as yet unclear. With its sensitivity to electric and magnetic
fields over a wide range of frequencies, we have used the NV center as a noise
spectrometer to spectroscopically probe sources of surface-related decoherence,
differentiating between electric and magnetic origins. These studies guide the
ongoing development of quantum control and diamond surface preparation
techniques, pushing towards the ultimate goal of NV-based single nuclear spin
imaging.