Quasiparticle self-consistent GW calculation of Sr2RuO4 and SrRuO3

By using quasiparticle self-consistent GW calculations, we reexamined the electronic structure of Sr2RuO4 and SrRuO3. 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 -3 eV in Sr2RuO4 and the half-metallicity for SrRuO3 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.