Dynamical mean-field theory of a correlated gap formation in plutonium monochalcogenides

The correlated Kondo insulator state of the plutonium monochalcogenides is investigated using the dynamical mean-field theory (DMFT) in fluctuating-exchange approximation and the local-density approximation +U (LDA+U). The DMFT-dynamical fluctuations lead to a correlated insulator state at elevated temperature, in sharp contrast to the static LDA+U approach that fails to reproduce both the insulating behavior and anomalous lattice constant. The DMFT conversely predicts the experimentally observed anomalous increase of the gap with pressure and explains the lattice constant very well.