Amorphous System and Theory
Institute of semiconductors, CAS
No.A35, QingHua East Road, Haidian District, Beijing, China
Hui-Xiong Deng received his PhD from the Institute of Semiconductor, Chinese Academy of Sciences, in 2010. From March 2011 to February 2014, he worked as a Postdoctoral Fellow at National Renewable Energy Laboratory (NREL), USA. Currently, he is a Professor at the Institute of Semiconductors, Chinese Academy of Sciences. His research interests include semiconductor physics, defect physics in semiconductors and design of optoelectronic materials. He was awarded the Outstanding Youth Science Foundation of NSFC, and selected as the outstanding member of Young Innovation Promotion Association of Chinese Academy of Sciences. He has published more than 70 SCI papers in Nature Energy, Phys. Rev. Lett., Nature Comm, Phys. Rev. X, Phys. Rev. B, Adv. Mater. and other journals.
Abstract for Presentation
A realistic dimension-independent approach for charged-defect calculations in semiconductors
First-principles calculations of charged defects have become a cornerstone of research in semiconductors and insulators by providing insights into their fundamental physical properties. But current standard approach using the so-called “jellium model” has encountered both conceptual ambiguity and computational difficulty, especially for low-dimensional semiconducting materials. In this presentation, we propose a more physical and straightforward “transfer to real state” model (TRSM) to calculate the formation energies of charged defects in both three-dimensional (3D) bulk and low-dimensional semiconductors. Within this universal model, the ionized electrons or holes are placed on the realistic host band-edge states instead of the virtual jellium state, therefore, rendering it not only naturally keeps the supercell charge neutral, but also has clear physical meaning, thus can be easily extended to study other physical properties such as exciton binding energy, free carrier bound to the defect in low-dimensional systems. This realistic model reproduces the same accuracy as the traditional jellium model for most of the 3D semiconducting materials, and remarkably, for the low-dimensional structures, it can cure the divergence caused by the artificial long-range electrostatic energy encountered in the jellium model, and hence gives meaningful formation energies of defects in charged state and transition energies of the corresponding defects. Our realistic method, therefore, will have a significant impact on the study of defect physics in all low-dimensional systems including quantum dots, nanowires, surfaces, interfaces, and 2D materials.
Figure 1. Schematics of low-dimensional charged defect calculations within jellium model and TRSM.
 H.-X. Deng*, S.-H. Wei*, Phys. Rev. Lett. 120, 039601 (2018)
 H.-X. Deng*, J-W. Luo*, S.-S. Li, S.-H. Wei*, et. al., Phys. Rev. B 101, 165306 (2020)
WELCOME TO CHINA TO ATTEND THE ICANS
23-26 August, Nanjing, China
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