Stable two-dimensional dumbbell stanene: a quantum spin Hall insulator

TL;DR

This paper predicts a novel dumbbell-structured stanene as a quantum spin Hall insulator with tunable properties, suitable for experimental realization and potential applications in quantum technologies.

Contribution

It introduces a new dumbbell stanene structure, demonstrates its topological insulator behavior, and proposes compatible substrates for experimental synthesis.

Findings

Dumbbell stanene is a 2D topological insulator with an inverted band gap.

The band gap can be tuned by applying compressive strain.

Suitable substrates like boron nitride and reconstructed InSb surfaces support its non-trivial topology.

Abstract

We predict from first-principles calculations a novel structure of stanene with dumbbell units (DB), and show that it is a two-dimensional topological insulator with inverted band gap which can be tuned by compressive strain. Furthermore, we propose that the boron nitride sheet and reconstructed ($2\times2$) InSb(111) surfaces are ideal substrates for the experimental realization of DB stanene, maintaining its non-trivial topology. Combined with standard semiconductor technologies, such as magnetic doping and electrical gating, the quantum anomalous Hall effect, Chern half metallicity and topological superconductivity can be realized in DB stanene on those substrates. These properties make the two-dimensional supported stanene a good platform for the study of new quantum spin Hall insulator as well as other exotic quantum states of matter.