Quantum spin Hall effect in a transition metal oxide Na2IrO3

TL;DR

This paper theoretically predicts that Na2IrO3, a 5d transition metal oxide, exhibits a layered quantum spin Hall effect influenced by strong spin-orbit coupling and electron correlations, with edge and bulk magnetic ordering.

Contribution

It introduces a theoretical model showing Na2IrO3 as a layered quantum spin Hall insulator with correlated magnetic phases.

Findings

Na2IrO3 is predicted to be a layered quantum spin Hall system.

Edge antiferromagnetic order develops before bulk magnetic order.

Electron correlations induce magnetic ordering at low temperatures.

Abstract

We study theoretically the electronic states in a $5d$ transition metal oxide Na$_2$IrO$_3$, in which both the spin-orbit interaction and the electron correlation play crucial roles. Tight-binding model analysis together with the fisrt-principles band structure calculation predicts that this material is a layered quantum spin Hall system. Due to the electron correlation, an antiferromagnetic order first develops at the edge, and later inside the bulk at low temperatures.