Approaching a Minimal Topological Electronic Structure in Antiferromagnetic Topological Insulator MnBi2Te4 via Surface Modification

Aiji Liang; Cheng Chen; Huijun Zheng; Wei Xia; Kui Huang; Liyang Wei; Haifeng Yang; Yujie Chen; Xin Zhang; Xuguang Xu; Meixiao Wang; Yanfeng Guo; Lexian Yang; Zhongkai Liu; Yulin Chen

doi:10.1021/acs.nanolett.1c04930

Approaching a Minimal Topological Electronic Structure in Antiferromagnetic Topological Insulator MnBi₂Te₄ via Surface Modification

Nano Lett. 2022 Jun 8;22(11):4307-4314. doi: 10.1021/acs.nanolett.1c04930. Epub 2022 May 23.

Authors

Aiji Liang^{1

2}, Cheng Chen³, Huijun Zheng¹, Wei Xia^{1

2}, Kui Huang¹, Liyang Wei¹, Haifeng Yang¹, Yujie Chen⁴, Xin Zhang¹, Xuguang Xu^{1

2}, Meixiao Wang^{1

2}, Yanfeng Guo^{1

2}, Lexian Yang^{4

5}, Zhongkai Liu^{1

2}, Yulin Chen^{1

2

3

4}

Affiliations

¹ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
² ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China.
³ Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, U.K.
⁴ State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
⁵ Frontier Science Center for Quantum Information, Beijing 100084, China.

PMID: 35604392
DOI: 10.1021/acs.nanolett.1c04930

Abstract

The topological electronic structure plays a central role in the nontrivial physical properties in topological quantum materials. A minimal, "hydrogen-atom-like" topological electronic structure is desired for research. In this work, we demonstrate an effort toward the realization of such a system in the intrinsic magnetic topological insulator MnBi₂Te₄, by manipulating the topological surface state (TSS) via surface modification. Using high resolution laser- and synchrotron-based angle-resolved photoemission spectroscopy (ARPES), we found the TSS in MnBi₂Te₄ is heavily hybridized with a trivial Rashba-type surface state (RSS), which could be efficiently removed by the in situ surface potassium (K) dosing. By employing multiple experimental methods to characterize K dosed surface, we attribute such a modification to the electrochemical reactions of K clusters on the surface. Our work not only gives a clear band assignment in MnBi₂Te₄ but also provides possible new routes in accentuating the topological behavior in the magnetic topological quantum materials.

Keywords: ARPES; MnBi2Te4; magnetic topological insulator; potassium dosing; topological surface state.