Large-gap quantum anomalous Hall states induced by functionalizing buckled Bi-III monolayer/Al2O3

Suhua Jin, Yunyouyou Xia, Wujun Shi, Jiayu Hu, Ralph Claessen, Werner Hanke, Ronny Thomale, and Gang Li
Phys. Rev. B 106, 125151 – Published 29 September 2022
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Abstract

Chiral edge modes inherent to the topological quantum anomalous Hall (QAH) effect are a pivotal topic of contemporary condensed matter research aiming at future quantum technology and application in spintronics. A large topological gap is vital to protecting against thermal fluctuations and thus enabling a higher operating temperature. From first-principles calculations, we propose Al2O3 as an ideal substrate for atomic monolayers consisting of Bi and group-III elements, in which a large-gap quantum spin Hall effect can be realized. Additional half-passivation with nitrogen then suggests a topological phase transition to a large-gap QAH insulator. By effective tight-binding modeling, we demonstrate that Bi-III monolayer/Al2O3 is dominated by px,py orbitals, with subdominant pz orbital contributions. The topological phase transition into the QAH is induced by Zeeman splitting, where the off-diagonal spin exchange does not play a significant role. The effective model analysis promises utility far beyond Bi-III monolayer/Al2O3, as it should generically apply to systems dominated by px,py orbitals with a band inversion at Γ.

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  • Received 6 May 2022
  • Accepted 13 September 2022

DOI:https://doi.org/10.1103/PhysRevB.106.125151

©2022 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Suhua Jin1,*, Yunyouyou Xia1,2,*, Wujun Shi3,4, Jiayu Hu1, Ralph Claessen5,6, Werner Hanke7,6, Ronny Thomale7,6, and Gang Li1,2,†

  • 1School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
  • 2ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, China
  • 3Center for Transformative Science, ShanghaiTech University, Shanghai 201210, China
  • 4Shanghai High Repetition Rate XFEL and Extreme Light Facility (SHINE), ShanghaiTech University, Shanghai 201210, China
  • 5Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
  • 6Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
  • 7Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany

  • *S.J. and Y.X. contributed equally to this work.
  • ligang@shanghaitech.edu.cn

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Issue

Vol. 106, Iss. 12 — 15 September 2022

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