Quasiparticle self-consistent GW calculation of Sr2RuO4 and SrRuO3

By using quasiparticle self-consistent GW calculations, we reexamined the electronic structure of ${\mathrm{Sr}}₂{\mathrm{RuO}}₄$ and ${\mathrm{SrRuO}}₃$. Our calculations show that the correlation effects beyond the conventional local density approximation and generalized gradient approximation are reasonably well captured by the QSGW self-energy without any ad hoc parameter or any ambiguity related to the double-counting and the downfolding issues. While spectral weight transfer to the lower and upper Hubbard band is not observed, the noticeable bandwidth reduction and effective-mass enhancement are obtained. Important features in the electronic structures that have been debated over the last decades such as the photoemission spectra at around $\ensuremath{-}3$ eV in ${\mathrm{Sr}}₂{\mathrm{RuO}}₄$ and the half-metallicity for ${\mathrm{SrRuO}}₃$ are discussed in the light of our QSGW results and in comparison with the previous studies. The promising aspects of QSGW are highlighted as a first-principles calculation method to describe the moderately correlated $4d$ transition-metal oxides along with the limitations of QSGW.