Fully ab initio electronic structure of Ca2RuO4

The reliable ab initio description of strongly correlated materials is a long-sought capability in condensed matter physics. The combination of $GW$ and extended dynamical mean-field theory (EDMFT) method is a promising scheme which provides a self-consistent description of correlations and screening, and does not require user-provided parameters. In order to test the reliability of this $GW$+EDMFT approach we apply it to the experimentally well characterized perovskite compound ${\mathrm{Ca}}₂{\mathrm{RuO}}₄$, in which a temperature-dependent structural deformation drives a paramagnetic metal-insulator transition. Our results demonstrate that the nonlocal polarization and self-energy components introduced by $GW$ are essential for setting the correct balance between interactions and bandwidths, and that the $GW+\mathrm{EDMFT}$ scheme produces remarkably accurate predictions of the electronic properties of this strongly correlated material.