Combined Semilocal Exchange Potential with Dynamical Mean-Field Theory

Abstract: The modern semilocal exchange potential is an accurate and efficient approximation to the exact exchange potential of density functional theory. We tried to combine it with the dynamical mean-field theory to derive a new first-principles many-body approach for studying correlated electronic materials. As a paradigm, this approach was employed to investigate the electronic structures and optical properties of strongly correlated ionic insulator YbS. Compared to the standard density functional theory plus dynamical mean-field theory which surprisingly failed to give an insulating solution, the new approach correctly captured all of the important characteristics of YbS. Not only an energy gap between a fully occupied Yb-4$f$ state and an unoccupied conduction band, but also an absence of Drude peak in the optical conductivity $\sigma(\omega)$ were successfully reproduced.