NT4.1: Excitonic Properties of 2D Materials and Heterostructures
Session Chairs
Linyou Cao
Thomas Mueller
Tuesday PM, March 29, 2016
PCC North, 100 Level, Room 129 B
2:30 PM - *NT4.1.01
The Valley Hall Effect in MoS2 Transistors
Paul McEuen 1,Kin Fai Mak 2,Kathryn McGill 1,Jiwoong Park 1
1 Cornell Univ Ithaca United States,2 Physics Penn State State College United States
Show AbstractElectrons in two-dimensional crystals with a honeycomb lattice structure possess a valley degree of freedom (DOF) in addition to charge and spin. These systems are predicted to exhibit an anomalous Hall effect whose sign depends on the valley index. Here, we report the observation of this so-called valley Hall effect (VHE). Monolayer MoS2 transistors are illuminated with circularly polarized light, which preferentially excites electrons into a specific valley, causing a finite anomalous Hall voltage whose sign is controlled by the helicity of the light. No anomalous Hall effect is observed in bilayer devices, which have crystal inversion symmetry. Our observation of the VHE opens up new possibilities for using the valley DOF as an information carrier in next-generation electronics and optoelectronics. Time permitting, I will also discuss the properties of other novel 2D materials under study in our laboratory.
3:00 PM - NT4.1.02
Engineering Substrate Interactions for High Luminescence Efficiency of Transition Metal Dichalcogenide Monolayers
Yifei Yu 1,Yiling Yu 1,Linyou Cao 1
1 North Carolina State Univ Raleigh United States,
Show AbstractTwo-dimensional (2D) transition metal dichalcogenides (TMDCs) such as monolayer MoS2 and WS2 are promising for developing truly atomic-scale light emission devices. Despite perfe