MRS Meetings and Events

 

SF06.09.05 2022 MRS Fall Meeting

Symmetry-Breaking and Reconstruction at Point Defects in Solids

When and Where

Dec 1, 2022
9:45am - 10:00am

Sheraton, 3rd Floor, Fairfax A/B

Presenter

Co-Author(s)

Seán Kavanagh1,Irea Mosquera-Lois2,Aron Walsh2,David Scanlon3

University College London & Imperial College London1,Imperial College London2,University College London3

Abstract

Seán Kavanagh1,Irea Mosquera-Lois2,Aron Walsh2,David Scanlon3

University College London & Imperial College London1,Imperial College London2,University College London3
Point defects are a universal feature of crystalline materials. Their identification is often addressed by combining experimental measurements with theoretical models. The standard approach of simulating defects is, however, prone to miss the ground state atomic configurations associated with energy-lowering reconstructions from the idealised crystallographic environment.<sup>1–5</sup> Missed ground states compromise the accuracy of calculated properties.<br/> <br/>To address this issue, we report an approach to efficiently navigate the defect configurational landscape using targeted bond distortions and rattling.<sup>6</sup> Application of our workflow to a range of materials (CdTe, GaAs, Sb<sub>2</sub>S<sub>3</sub>, Sb<sub>2</sub>Se<sub>3</sub>, CeO<sub>2</sub>) reveals symmetry breaking in each host crystal that is not found via conventional local minimization techniques. The point defect distortions are classified by the associated physico-chemical factors. We demonstrate the impact of these defect distortions on derived properties, including formation energies, concentrations and charge transition levels. Our work presents a step forward for quantitative modelling of imperfect solids.<br/> <br/>1. Arrigoni, M. & Madsen, G. K. H. Evolutionary computing and machine learning for discovering of low-energy defect configurations. <i>npj Comput Mater</i> <b>7</b>, 1–13 (2021).<br/>2. Mosquera-Lois, I. & Kavanagh, S. R. In search of hidden defects. <i>Matter</i> <b>4</b>, 2602–2605 (2021).<br/>3. Lany, S. & Zunger, A. Metal-Dimer Atomic Reconstruction Leading to Deep Donor States of the Anion Vacancy in II-VI and Chalcopyrite Semiconductors. <i>Phys. Rev. Lett.</i> <b>93</b>, 156404 (2004).<br/>4. Kavanagh, S. R., Walsh, A. & Scanlon, D. O. Rapid Recombination by Cadmium Vacancies in CdTe. <i>ACS Energy Lett.</i> <b>6</b>, 1392–1398 (2021).<br/>5. Kavanagh, S. R., Scanlon, D. O., Walsh, A. & Freysoldt, C. Impact of metastable defect structures on carrier recombination in solar cells. <i>Faraday Discuss.</i> (2022) doi:10.1039/D2FD00043A.<br/>6. Mosquera-Lois, I., Kavanagh, S. R., Walsh, A., Scanlon, D. O. Symmetry-breaking and reconstruction at point defects in solids. <i>npj Computational Materials </i>(In submission)

Keywords

defects

Symposium Organizers

Cody Dennett, Massachusetts Institute of Technology
Marat Khafizov, The Ohio State University
Lucas Lindsay, Oak Ridge National Laboratory
Zhiting Tian, Cornell University

Publishing Alliance

MRS publishes with Springer Nature