Potential superconducting interfaces in polar ABO3/Ba(Sr)BiO3 heterostructures

Abstract

We predict that interfacing the known superconducting oxide Ba(Sr)BiO3 with a polar terminated perovskite oxide leads to a two-dimensional (2D) electron and/or hole gasses with a density similar to superconducting K-doped bismuthates. These interfaces have the potential for high-Tc superconductivity without the strong scattering present in randomly chemically substituted bismuthates. We present a detailed density functional theory (DFT) based study of the electronic structure of heterostructures involving polar 001 oriented LaLuO3 (LLO) and SrBiO3 (SBO) alternating layers. Beyond the thickness of four unit cells, 2D electron and hole gasses are formed at opposite interfaces of SrBiO3 with sheet charge densities on the order of 1014cm−2. The electron and hole gasses exist around the Y (X) and M points of the Brillouin zone, respectively. The separation of the gasses and therefore their interactions can be regulated by the SBO layer thickness. This provides a platform in which charge density waves, excitonic insulators or condensates, and superconductors compete for the ground state with the potential for new physical properties including high-Tc superconductivity.

Source-reported materials — not catalogue approval

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