Koopmans' theorem as the mechanism of nearly gapless surface states in self-doped magnetic topological insulators

Chen，Weizhao1; Zhao，Yufei1; Yao，Qiushi1; Zhang，Jing1; Liu，Qihang1,2,3

2021-05-03

10.1103/PhysRevB.103.L201102

Physical Review B   影响因子和分区

2469-9950

2469-9969

The magnetization-induced gap at the surface state is widely believed to be the kernel of magnetic topological insulators (MTIs) because of its relevance to various topological phenomena, such as the quantum anomalous Hall effect and the axion insulator phase. However, whether the magnetic gap exists in an intrinsic MTI, such as MnBi2Te4, still remains elusive, with significant discrepancies between theoretical predictions and various experimental observations. Here, including the previously overlooked self-doping in real MTIs, we find that in general a doped MTI prefers a ground state with a gapless surface state. We use a simple model based on Koopmans' theorem to elucidate the mechanism and further demonstrate it in the self-doped MnBi2Te4/(Bi2Te3)n family through first-principles calculations. Our work sheds light on the design principles of MTIs with magnetic gaps by revealing the critical role of doping effects in understanding the delicate interplay between magnetism and topology.

SCI ; EI

英语

第一 ; 通讯

WOS:000647487800009

20212110406281

Bismuth compounds ; Calculations ; Electric insulators ; Ground state ; Quantum Hall effect ; Surface states ; Topology

Mathematics:921 ; Combinatorial Mathematics, Includes Graph Theory, Set Theory:921.4 ; Classical Physics; Quantum Theory; Relativity:931 ; Quantum Theory; Quantum Mechanics:931.4

PHYSICS

2-s2.0-85106356958

Scopus

1.Shenzhen Institute for Quantum Science and Engineering,Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China
2.Guangdong Provincial Key Laboratory of Computational Science and Material Design,Southern University of Science and Technology,Shenzhen,518055,China
3.Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices,Southern University of Science and Technology,Shenzhen,518055,China

Chen，Weizhao,Zhao，Yufei,Yao，Qiushi,et al. Koopmans' theorem as the mechanism of nearly gapless surface states in self-doped magnetic topological insulators[J]. Physical Review B,2021,103(20).

Chen，Weizhao,Zhao，Yufei,Yao，Qiushi,Zhang，Jing,&Liu，Qihang.(2021).Koopmans' theorem as the mechanism of nearly gapless surface states in self-doped magnetic topological insulators.Physical Review B,103(20).

Chen，Weizhao,et al."Koopmans' theorem as the mechanism of nearly gapless surface states in self-doped magnetic topological insulators".Physical Review B 103.20(2021).