Author(s): Xiao, J (Xiao, Jin); Yang, KK (Yang, Kaike); Guo, D (Guo, Dan); Shen, T (Shen, Tao); Deng, HX (Deng, Hui-Xiong); Li, SS (Li, Shu-Shen); Luo, JW (Luo, Jun-Wei); Wei, SH (Wei, Su-Huai)
Source: PHYSICAL REVIEW B Volume: 101 Issue: 16 Article Number: 165306 DOI: 10.1103/PhysRevB.101.165306 Published: APR 16 2020
Abstract: 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 paper, we propose a more physical and straightforward "transfer to real state" model 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-energy levels of the corresponding defects. Our realistic method, therefore, will have significant impact for the study of defect physics in all low-dimensional systems.
Accession Number: WOS:000526036000003
ISSN: 2469-9950
eISSN: 2469-9969
Full Text: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.165306