Tuning the electronic and magnetic ground states of layered honeycomb material Na2IrO3via strain engineering

Abstract

First-principles calculations are used to investigate strain-induced tuning of the electronic and magnetic ground states in Na₂IrO₃. The pseudo-spin state and the Mott insulating phase remain robust under strain. At 3% tensile strain, a transition from an indirect to a direct band gap occurs, governed primarily by strong electronic correlations rather than spin–orbit coupling. A concurrent magnetic transition from zigzag antiferromagnetic (AFM) to ferromagnetic (FM) order is also observed. The resulting ferromagnetic semiconducting phase under strain indicates promise for spintronic and energy applications, including in microwave devices, permanent magnets, spin filters, and tunneling magnetoresistance (TMR) devices. The singlet–triplet gap, indicative of the isotropic exchange J, is minimized at 3% strain, offering favorable conditions for realizing a Kitaev spin liquid state.