Native point defects and their implications for the Dirac point gap at MnBi<sub>2</sub>Te<sub>4</sub>(0001)

ORAL

Abstract

The Dirac point gap at the surface of the antiferromagnetic topological insulator MnBi2Te4 (MBT) is a highly debated issue [1-3]. While the early photoemission measurements reported on large gaps in agreement with theoretical predictions, other experiments found vanishingly small splitting of the MBT Dirac cone. Here, we study the effect of the native point defects on the MBT surface electronic structure using the density functional theory calculations [4]. The results of our scanning tunneling microscopy images simulations are consistent with the presence of the BiTe antisites (Bi atoms at the Te sites) and MnBi substitutions (Mn atoms at the Bi sites). Our surface electronic structure calculations show that, due to the predominant localization of the topological surface state near the Bi layers, MnBi defects can cause a strong reduction of the MBT Dirac point gap [4], given the recently proved [5] antiparallel alignment of the MnBi moments with respect to those of the Mn layer. Our results provide important insights into the MBT Dirac point gap mystery.

1 M Otrokov et al, Nature 576, 412 (2019)

2 Y Hao et al, Phys. Rev. X 9, 041038 (2019)

3 A Shikin et al, Phys. Rev. B 104, 115168 (2021)

4 M Garnica, M. Otrokov et al, arXiv:2109.01615

5 Y Lai et al, Phys. Rev. B 103, 184429 (2021)

*We acknowledge support by the Spanish Ministerio de Ciencia e Innovacion (Grant no. PID2019-103910GB-I00, PGC2018–093291–B–I00, PGC2018-097028–A–I00 and PGC2018-098613–B–C21), Saint Petersburg State University (project ID No. 73028629), the 'Severo Ochoa' Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686), Postdoctoral Junior Leader Fellowship Programme from "la Caixa" Banking Foundation, the Science Development Foundation under the President of the Republic of Azerbaijan (Grant No. EIF-BGM-4-RFTF-1/2017-21/04/1-M-02), Russian Science Foundation (Grant No. 18-12-00062), and Russian Foundation of Basic Researches (Grant No. 20-32-70179)

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Publication: M. Garnica, M. M. Otrokov, et al., arXiv:2109.01615 (2021)

Presenters

  • Mikhail M Otrokov

    • Centro de Fisica de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastian, Basque Country, Spain

Authors

  • Mikhail M Otrokov

    • Centro de Fisica de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastian, Basque Country, Spain

  • Manuela Garnica

    • Instituto Madrile˜no de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain

  • Pablo Casado Aguilar

    • Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, 28049 Madrid, Spain

  • Ilya I Klimovskikh

    • Saint Petersburg State University, 198504 Saint Petersburg, Russia

  • Dmitry Estyunin

    • Saint Petersburg State University, 198504 Saint Petersburg, Russia

  • Ziya S Aliev

    • Azerbaijan State Oil and Industry University, AZ1010 Baku, Azerbaijan

  • Imamaddin Amiraslanov

    • Institute of Physics, National Academy of Sciences of Azerbaijan, AZ1143 Baku, Azerbaijan

  • Nadir A Abdullayev

    • Baku State University, AZ1148 Baku, Azerbaijan

  • Vladimir N Zverev

    • Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia

  • Mahammad B Babanly

    • 0Institute of Catalysis and Inorganic Chemistry, Azerbaijan National Academy of Science, AZ1143 Baku, Azerbaijan

  • Andres Arnau

    • Departamento de Fisica de Materiales UPV/EHU, 20080 Donostia-San Sebastian, Basque Country, Spain

  • Nazim T Mamedov

    • Institute of Physics, National Academy of Sciences of Azerbaijan, AZ1143 Baku, Azerbaijan

  • Amadeo L Vazquez de Parga

    • Autonomous University of Madrid
    • Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, 28049 Madrid, Spain

  • Alexander M Shikin

    • Saint Petersburg State University, 198504 Saint Petersburg, Russia

  • Evgueni V Chulkov

    • Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastian, Basque Country, Spain

  • Rodolfo Miranda

    • IMDEA Nanociencia, C/Faraday 9, 28049 Madrid, Spain
    • Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain