Possibility of Realizing Quantum Spin Hall Effect at Room Temperature in Stanene/Al2O3(0001)

TL;DR

This study demonstrates that stanene on Al2O3(0001) substrate can host a sizable quantum spin Hall effect at room temperature, due to its topologically nontrivial band gap and stable decoupled structure, promising for future electronic devices.

Contribution

The paper shows that stanene on Al2O3(0001) can realize a large band gap QSH insulator at room temperature, a significant advancement over previous materials.

Findings

Stanene on Al2O3(0001) has a ~0.25 eV topologically nontrivial band gap.

Stanene remains structurally stable and electronically decoupled from the substrate.

The physical mechanism is general, opening new avenues for room temperature QSH devices.

Abstract

Two-dimensional quantum spin Hall (QSH) insulators with reasonably wide band gaps are imperative for the development of various innovative technologies. Through systematic density functional calculations and tight-binding simulations, we found that stanene on {\alpha}-alumina surface may possess a sizeable topologically nontrivial band gap (~0.25 eV) at the {\Gamma} point. Furthermore, stanene is atomically bonded to but electronically decoupled from the substrate, providing high structural stability and isolated QSH states to a large extent. The underlying physical mechanism is rather general, and this finding may lead to the opening of a new vista for the exploration of QSH insulators for room temperature device applications.