Quantum Spin Hall Effect in a Transition Metal OxideNa2IrO3

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