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arXiv · 1604.03064

Four allotropes of semiconducting layered Arsenic which switch into a topological insulator via an electric field: A computational study

Sougata Mardanya·Vinay Kumar Thakur·Somnath Bhowmick·Amit Agarwal
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Abstract

We propose four different thermodynamically stable structural phases of arsenic monolayers based on ab-initio density functional theory calculations all of which undergo a topological phase transition on application of a perpendicular electric field. All the four arsenic monolayer allotropes have a wide band gap, varying from 1.21 eV to 3.0 eV (based on GW calculations), and in general they undergo a metal-insulator quantum phase transition on application of uniaxial in-layer strain. Additionally an increasing transverse electric field induces band-inversion at the Γ point in all four monolayer allotropes, leading to a nontrivial topological phase (insulating for three and metallic for one allotrope), characterized by the switching of the Z2 index, from 0 (before band inversion) to 1 (after band inversion). The topological phase tuned by the transverse electric field, should support spin-separated gapless edge states which should manifest in quantum spin Hall effect.

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Sougata Mardanya, Vinay Kumar Thakur, Somnath Bhowmick, Amit Agarwal. 2016-06-29. Four allotropes of semiconducting layered Arsenic which switch into a topological insulator via an electric field: A computational study. https://doi.org/10.1103/physrevb.94.035423

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