First Principles Prediction of Topological Phases in Thin Films of Pyrochlore Iridates

While the theoretical and experimental study of topological phases of matter has experienced rapid growth over the last few years, there remain a relatively small number of material classes that have been experimentally shown to host these phases. Most of these materials contain bismuth, and none so far are oxides. In this work we make materials-specific predictions for topological phases using density functional theory combined with Hartree-Fock theory that includes the full orbital structure of the relevant iridium d-orbitals and the strong but finite spin-orbit coupling strength. We find Y2Ir2O7 bilayer and trilayer films grown along the [111] direction can support topological metallic phases with a direct gap of up to 0.05 eV, which could potentially bring transition metal oxides to the fore as a new class of topological materials with potential applications in oxide electronics.