Two-dimensional antiferromagnetic Dirac fermions in monolayer TaCoTe2

Si Li, Ying Liu, Zhi-Ming Yu, Yalong Jiao, Shan Guan, Xian-Lei Sheng, Yugui Yao, and Shengyuan A. Yang
Phys. Rev. B 100, 205102 – Published 4 November 2019

Abstract

Dirac points in two-dimensional (2D) materials have been a fascinating subject of research. Recently, it has been theoretically predicted that Dirac points may also be stabilized in 2D magnetic systems. However, it remains a challenge to identify concrete 2D materials which host such magnetic Dirac points. Here, based on first-principles calculations and theoretical analysis, we propose a stable 2D material, the monolayer TaCoTe2, as an antiferromagnetic (AFM) 2D Dirac material. We show that it has an AFM ground state with an out-of-plane Néel vector. It hosts a pair of 2D AFM Dirac points on the Fermi level in the absence of spin-orbit coupling (SOC). When the SOC is considered, a small gap is opened at the original Dirac points. Meanwhile, another pair of Dirac points appear on the Brillouin zone boundary below the Fermi level, which are robust under SOC and have a type-II dispersion. Such a type-II AFM Dirac point has not been observed before. We further show that the location of this Dirac point as well as its dispersion type can be controlled by tuning the Néel vector orientation.

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  • Received 21 August 2019

DOI:https://doi.org/10.1103/PhysRevB.100.205102

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Si Li1,2,3, Ying Liu3,4, Zhi-Ming Yu3, Yalong Jiao3, Shan Guan5, Xian-Lei Sheng3,6, Yugui Yao2,*, and Shengyuan A. Yang3,7,†

  • 1School of Physics and Electronics, Hunan Normal University, Changsha, Hunan 410081, China
  • 2Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing 100081, China
  • 3Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
  • 4Institute for Theoretical Physics and Astrophysics, University of Würzburg, Würzburg 97074, Germany
  • 5State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • 6Department of Physics, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (MOE), Beihang University, Beijing 100191, China
  • 7Center for Quantum Transport and Thermal Energy Science, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China

  • *ygyao@bit.edu.cn
  • shengyuan_yang@sutd.edu.sg

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Issue

Vol. 100, Iss. 20 — 15 November 2019

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