Visualizing topological edge states of single and double bilayer Bi supported on multibilayer Bi(111) films

Lang Peng, Jing-Jing Xian, Peizhe Tang, Angel Rubio, Shou-Cheng Zhang, Wenhao Zhang, and Ying-Shuang Fu
Phys. Rev. B 98, 245108 – Published 5 December 2018

Abstract

Freestanding single bilayer Bi(111) is a two-dimensional topological insulator with edge states propagating along its perimeter. Given the interlayer coupling experimentally, the topological nature of Bi(111) thin films and the impact of the supporting substrate on the topmost Bi bilayer are still under debate. Here, combined with scanning tunneling microscopy and first-principles calculations, we systematically study the electronic properties of Bi(111) thin films grown on a NbSe2 substrate. Two types of nonmagnetic edge structures, i.e., a conventional zigzag edge and a 2 × 1 reconstructed edge, coexist alternately at the boundaries of single bilayer islands, the topological edge states of which exhibit remarkably different energy and spatial distributions. Prominent edge states are persistently visualized at the edges of both single and double bilayer Bi islands, regardless of the underlying thickness of Bi(111) thin films. We provide an explanation for the topological origin of the observed edge states that is verified with first-principles calculations. Our paper clarifies the long-standing controversy regarding the topology of Bi(111) thin films and reveals the tunability of topological edge states via edge modifications.

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  • Received 24 April 2018

DOI:https://doi.org/10.1103/PhysRevB.98.245108

©2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Lang Peng1, Jing-Jing Xian1, Peizhe Tang2,3,*, Angel Rubio3, Shou-Cheng Zhang2,4, Wenhao Zhang1,†, and Ying-Shuang Fu1,‡

  • 1School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
  • 2Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA
  • 3Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
  • 4Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA

  • *peizhe.tang@mpsd.mpg.de
  • wenhaozhang@hust.edu.cn
  • yfu@hust.edu.cn

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Issue

Vol. 98, Iss. 24 — 15 December 2018

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