All-electron quasiparticle self-consistent GW for molecules and periodic systems within the numerical atomic orbital framework

We report an all-electron implementation of the quasiparticle self-consistent GW (QSGW) method for molecular and periodic systems within the framework of numerical atomic orbitals (NAOs), as implemented in the LibRPA software package. Our implementation is based on the space-time formalism, combined with the localized resolution-of-identity approximation to treat two-electron quantities. We found that analytical continuation of the self-energy matrix, in combination with the "Mode B" QSGW scheme, can yield stable self-consistent quasiparticle energy spectra. Systematic benchmark calculations on molecules and crystalline solids (including typical semiconductors and wide-gap insulators) demonstrate that our NAO-based QSGW scheme yields molecular ionization potentials and quasiparticle bandgaps for periodic solids that are consistent with reference results from established implementations. Our work opens the way for large-scale QSGW calculations, taking advantage of the NAO-based low-scaling algorithm previously developed for the G0W0 method.