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

Yandong Ma, Liangzhi Kou, Aijun Du, Thomas Heine

Research output: Contribution to journalArticle

22 Citations (Scopus)

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. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)3412-3420
Number of pages9
JournalNano Research
Volume8
Issue number10
DOIs
Publication statusPublished - 2015 Oct 1

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Electrical and Electronic Engineering

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