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

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 iridum $d$-orbitals and the strong but finite spin-orbit coupling strength. We find Y$_2$Ir$_2$O$_7$ bilayer and trilayer films grown along the [111] direction can respectively support a Z$_2$ topological metallic phase and a Chern metallic phase with a direct gap of up to 0.02 eV. These results could potentially bring transition metal oxides to the fore as a new class of topological materials with potential applications in oxide electronics.