First-Principles Investigation of Sb Doping and Strain Effects in MnBi_2-xSb_xTe₄

Chen-Chia Hsu^1*, Yu-Chang Chen², Ken-Ming Lin², Cheng-Chien Chen³, Jiunn-Yuan Lin¹

¹Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
³Department of Physics, University of Alabama at Birmingham, Birmingham, USA

* Presenter:Chen-Chia Hsu, email:tonyhsu.sc10@nycu.edu.tw

MnBi₂Te₄ has garnered significant attention due to its unique properties as an antiferromagnetic topological insulator. The material also could transform into a potential Weyl semimetal under magnetic field, however with the challenge to pin the Fermi level within the bulk band gap. To address this challenge, previous studies have considered doping and strain effects as potential solutions. In this study, we perform first-principles density functional theory (DFT) calculations to model the structural, electronic, and topological properties of MnBi_2-xSb_xTe₄. The virtual crystal approximation (VCA) and DFT+U methods are employed to study the combined effects of Sb doping and electron correlation, in a wide range of Sb doping and strain levels induced by uniaxial stress or hydrostatic pressure. Our ab initio studies provide a roadmap to guide corresponding experiments to modify the electronic structures of MnBi_2-xSb_xTe₄ for the realization of potential Weyl semimetals in the material.
We are grateful to NSTC of Taiwan and AFOSR of US for supporting this project (NSTC-110-2124-M-A49-007-MY3).

Keywords: Magnetic topological materials, First-principles calculation, Doping and strain effects