Topological edge states in single layers of honeycomb materials with strong spin-orbit coupling

TL;DR

This paper investigates the presence of topological edge states in single-layer honeycomb materials with strong spin-orbit coupling, revealing their characteristics and potential experimental signatures.

Contribution

It introduces an effective tight-binding model for these materials, demonstrating the existence of degenerate edge states and analyzing symmetry roles and disorder effects.

Findings

Linearly dispersing 1D edge states in zig-zag boundary shapes

Degenerate edge states at zone center and boundary

Implications for experimental detection and disorder effects

Abstract

We study possible edge states in single layers of honeycomb materials such as $\alpha$-RuCl$_3$ and A$_2$IrO$_3$ (A=Li, Na) with strong spin-orbit coupling (SOC). These two dimensional systems exhibit linearly dispersing one-dimensional (1D) edge states when their 1D boundary forms a zig-zag shape. Using an effective tight-binding model based on first principles band structure calculations including Hubbard U and SOC, we find degenerate edge states at the zone center and zone boundary. The roles of chiral symmetry and time-reversal symmetry are presented. The implications to experimental signatures and the effects of disorder are also discussed.