Monolayer Topological Insulators: Silicene, Germanene and Stanene

TL;DR

This paper reviews recent theoretical advances in monolayer topological insulators like silicene, germanene, and stanene, highlighting their quantum spin Hall effects, tunable band gaps, and potential for topological electronics.

Contribution

It provides a comprehensive analysis of the topological properties, phase diagrams, and electronic applications of honeycomb monolayer topological insulators.

Findings

Quantum spin Hall effects observed in silicene, germanene, stanene

Band gaps can be tuned via perpendicular electric fields

Explicit phase diagrams for topological phases in honeycomb systems

Abstract

We report the recent progress on the theoretical aspects of monolayer topological insulators including silicene, germanene and stanene, which are monolayer honeycomb structures of silicon, germanium and tin, respectively. They show quantum spin Hall effects in nature due to the spin orbit interaction. The band gap can be tuned by applying perpendicular electric field, which induces a topological phase transition. We also analyze the topological properties of generic honeycomb systems together with the classification of topological insulators. Phase diagram of topological insulators and superconductors in honeycomb systems are explicitly determined. We also investigate topological electronics including a topological field-effect transistor, the topological Kirchhoff's law and the topological spin-valleytronics.