Density-functional prediction of a spin-orbital entangled two-dimensional electron gas at LaAlO₃/SrIrO₃ (001) interface

With the recent advances on the epitaxial growth techniques, epitaxy grown ultrathin films of SrIrO₃ have brought in a considerable research interest as they exhibit thickness dependent metal-insulator transition and other interesting transport properties. SrIrO₃ is a Mott insulator below three or four layers of SrIrO₃ grown on the SrTiO₃ substrate. Using density-functional methods, we study the (001) interface between the non-polar SrIrO₃ and the polar LaAlO₃ material, where the LaO layer is in contact with the IrO₂ layer. We predict the formation of a spin-orbital entangled 2DEG at the interface due to the polar catastrophe, analogous to the n-type LaAlO₃/Sr₂IrO₄ interface¹.The predicted 2DEG is very well localized at a single layer of Ir near the interface occupying the J_eff =1/2 conduction bands (upper Hubbard band). The 2DEG leads to a ferromagnetic interface, which is different from the antiferromagnetic bulk.

¹ C. Bhandari and S. Satpathy, Phys. Rev. B 98, 041303(R) (2018)