Band structure engineering through iridium double perovskite heterostructure design in the presence of strong spin-orbit coupling

The designed heterostructure of two experimentally synthesized and theoretically studied double perovskites ${\mathrm{Sr}}_{2}{\mathrm{CeIrO}}_{6}$ and ${\mathrm{Sr}}_{2}{\mathrm{MgIrO}}_{6}$ is investigated using the electronic structure method of the first-principles density functional theory. A half-metallic electronic structure is observed originating from the interfacial Ir site, in contrast to the insulating state that was found in the bulk ingredients. Further, we obtain an AFM ground state which is also supported by the microscopic magnetic exchange interactions analysis. The electronic and magnetic interactions are highly anisotropic in nature. The metallic transport is significantly larger at the in-plane interface layer as compared to that of the out-of-plane, and further shows the signatures of the formation of a two-dimensional (2D) Fermi gas. The impact of spin-orbit coupling (SOC) is crucial as it opens up a pseudogap at ${\mathrm{E}}_{F}$. Our study also reveals the variation in the impact of SOC for the different layers of Ir present in the heterostructures. Our results influence the understanding of the device engineering utilizing the anisotropic transport at the confined 2D interface in the presence of strong SOC physics.