A tight binding model for ultrathin perovskite oxide monolayers

The oxides are a family of materials that exhibit strong correlation effects even when untwisted. For this reason, it is natural to study the twistronics of these materials, as altering the twist angle presents the possibility of introducing interesting moiré physics to these materials. A starting point for understanding the twistronics of bilayers is understanding the monolayer electronic structure. We present DFT calculations of the electronic structure of perovskite oxide monolayers in the n=1 Ruddelsden-Popper phase, A2TiO4 (A=Ca, Sr, Ba). We also present an ab initio tight-binding model as well as a minimal 3-band effective model for the valence bands of these materials.