Two-dimensional Topological Crystalline Insulator Phase in Sb/Bi Planar Honeycomb with Tunable Dirac Gap

We predict planar Sb/Bi honeycomb to harbor a two-dimensional (2D) topological crystalline insulator (TCI) phase based on first-principles computations. Although buckled Sb and Bi honeycombs support 2D topological insulator (TI) phases, their structure becomes planar under tensile strain. The planar...

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Bibliographic Details
Published in:Scientific reports 2016-01, Vol.6 (1), p.18993-18993, Article 18993
Main Authors: Hsu, Chia-Hsiu, Huang, Zhi-Quan, Crisostomo, Christian P., Yao, Liang-Zi, Chuang, Feng-Chuan, Liu, Yu-Tzu, Wang, Baokai, Hsu, Chuang-Han, Lee, Chi-Cheng, Lin, Hsin, Bansil, Arun
Format: Article
Language:English
Subjects:
639/301/1005/1007
639/301/119/2792
Electric fields
electronic devices
Gating
Honeycombs
Humanities and Social Sciences
MATERIALS SCIENCE
multidisciplinary
Science
topological insulators
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Summary:We predict planar Sb/Bi honeycomb to harbor a two-dimensional (2D) topological crystalline insulator (TCI) phase based on first-principles computations. Although buckled Sb and Bi honeycombs support 2D topological insulator (TI) phases, their structure becomes planar under tensile strain. The planar Sb/Bi honeycomb structure restores the mirror symmetry and is shown to exhibit non-zero mirror Chern numbers, indicating that the system can host topologically protected edge states. Our computations show that the electronic spectrum of a planar Sb/Bi nanoribbon with armchair or zigzag edges contains two Dirac cones within the band gap and an even number of edge bands crossing the Fermi level. Lattice constant of the planar Sb honeycomb is found to nearly match that of hexagonal-BN. The Sb nanoribbon on hexagonal-BN exhibits gapped edge states, which we show to be tunable by an out-of-the-plane electric field, providing controllable gating of edge state important for device applications.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep18993