Large-gap quantum spin hall insulator in single layer bismuth monobromide Bi4Br4

Jin Jian Zhou, Wanxiang Feng, Cheng Cheng Liu, Shan Guan, Yugui Yao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

160 Citations (Scopus)

Abstract

Quantum spin Hall (QSH) insulators have gapless topological edge states inside the bulk band gap, which can serve as dissipationless spin current channels. The major challenge currently is to find suitable materials for this topological state. Here, we predict a new large-gap QSH insulator with bulk direct band gap of ∼0.18 eV, in single-layer Bi4Br4, which could be exfoliated from its three-dimensional bulk material due to the weakly bonded layered structure. The band gap of single-layer Bi 4Br4 is tunable via strain engineering, and the QSH phase is robust against external strain. Moreover, because this material consists of special one-dimensional molecular chain as its basic building block, the single layer Bi4Br4 could be torn to ribbons with clean and atomically sharp edges. These nanoribbons, which have single-Dirac-cone edge states crossing the bulk band gap, are ideal wires for dissipationless transport. Our work thus provides a new promising material for experimental studies and practical applications of the QSH effect.

Original languageEnglish
Pages (from-to)4767-4771
Number of pages5
JournalNano Letters
Volume14
Issue number8
DOIs
Publication statusPublished - 13 Aug 2014

Keywords

  • Quantum spin Hall insulator
  • bismuth monobromide
  • dissipationless transport
  • first-principles calculations
  • topological edge states
  • two-dimensional materials

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