Non-local Coulomb interaction and correlated electronic structure of TaS$_2$: A GW+EDMFT study

Abstract

By means of $ab~initio$ computation schemes, we examine the low-energy electronic structure of monolayer TaS$_2$ in its low-temperature commensurate charge-density-wave structure. We estimate and take into account both local and non-local Coulomb correlations within cRPA (constrained random phase approximation) and GW+EDMFT (GW plus extended dynamical mean-field theory) method. Mott nature of its insulating phase is clearly identified. By increasing the level of nonlocal approximation from DMFT ($V=0$) to EDMFT and GW+EDMFT, a systematic change of charge screening effects is clearly observed while its quantitative effect on the electronic structure is small in the realistic Mott state.