Large-gap quantum spin Hall state in functionalized dumbbell stanene

Two-dimensional dumbbell (DB) stanene has been proposed as a promising candidate material for realizing quantum spin Hall effect (QSHE) by Tang et al. [Phys. Rev. B 90, 121408 (2014)]. However, the small bulk-gap limits its possible applications at room temperature. Based on first-principles calcula...

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Bibliographic Details
Published in:Applied physics letters 2016-02, Vol.108 (7)
Main Authors: Wang, Ya-ping, Ji, Wei-xiao, Zhang, Chang-wen, Li, Ping, Li, Feng, Wang, Pei-ji, Li, Sheng-shi, Yan, Shi-shen
Format: Article
Language:English
Subjects:
Applied physics
Band gap
Bismuth tellurides
Energy gap
First principles
Lattice strain
Materials selection
Quantum Hall effect
Spintronics
Substrates
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Summary:Two-dimensional dumbbell (DB) stanene has been proposed as a promising candidate material for realizing quantum spin Hall effect (QSHE) by Tang et al. [Phys. Rev. B 90, 121408 (2014)]. However, the small bulk-gap limits its possible applications at room temperature. Based on first-principles calculations, we predict that its band gap can be enhanced to 148 meV under methyl-functionalization, which can be further tuned by applying lattice strain. The QSHE is confirmed by s-px,y band inversion, topological invariant Z2 = 1, and helical gapless edge within bulk band gap. Notably, the characteristic properties of edge states, such as the large Fermi velocity and Dirac cone, can be modulated by edge modification. The effects of substrates on topological properties are explored when it is grown on various substrates, like SiC, h-BN, and Bi2Te3 sheets. These findings provide significant guidance for future fabrication and realistic applications of QSHE based on stanene in spintronics.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4942380