Group 14 element-based non-centrosymmetric quantum spin hall insulators with large bulk gap

Ma, Yandong, Kou, Liangzhi, Du, Aijun, & Heine, Thomas (2015) Group 14 element-based non-centrosymmetric quantum spin hall insulators with large bulk gap. Nano Research, 8(10), pp. 3412-3420.

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Abstract

To date, a number of two-dimensional (2D) topological insulators (TIs) have been realized in Group 14 elemental honeycomb lattices, but all are inversionsymmetric. Here, based on first-principles calculations, we predict a new family of 2D inversion-asymmetric TIs with sizeable bulk gaps from 105 meV to 284 meV, in X2–GeSn (X = H, F, Cl, Br, I) monolayers, making them in principle suitable for room-temperature applications. The nontrivial topological characteristics of inverted band orders are identified in pristine X2–GeSn with X = (F, Cl, Br, I), whereas H2–GeSn undergoes a nontrivial band inversion at 8% lattice expansion. Topologically protected edge states are identified in X2–GeSn with X = (F, Cl, Br, I), as well as in strained H2–GeSn. More importantly, the edges of these systems, which exhibit single-Dirac-cone characteristics located exactly in the middle of their bulk band gaps, are ideal for dissipationless transport. Thus, Group 14 elemental honeycomb lattices provide a fascinating playground for the manipulation of quantum states.

Impact and interest:

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9 citations in Web of Science®

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ID Code: 87462
Item Type: Journal Article
Refereed: Yes
Additional URLs:
Keywords: two-dimensional crystal, topological insulators, Dirac states, band inversion, strain engineering, Group 14 honeycomb lattice
DOI: 10.1007/s12274-015-0842-7
ISSN: 1998-0000
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: © 2015 Tsinghua University Press and Springer-Verlag Berlin
Heidelberg
Deposited On: 15 Sep 2015 06:08
Last Modified: 26 May 2016 00:32

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