Strong Correlation Effects on Topological Quantum Phase Transitions in Three Dimensions

摘要

We investigate the role of short-ranged electron-electron interactions in aparadigmatic model of three dimensional topological insulators, using dynamicalmean-field theory and focusing on non magnetically ordered solutions. Thenon-interacting band-structure is controlled by a mass term M, whose valuediscriminates between three different insulating phases, a trivial bandinsulator and two distinct topologically non-trivial phases. We characterizethe evolution of the transitions between the different phases as a function ofthe local Coulomb repulsion U and find a remarkable dependence of the U -Mphase diagram on the value of the local Hund's exchange coupling J. However,regardless the value of J, following the evolution of the topologicaltransition line between a trivial band insulator and a topological insulator,we find a critical value of U separating a continuous transition from afirst-order one. When the Hund's coupling is significant, a Mott insulator isstabilized at large U . In proximity of the Mott transition we observe theemergence of an anomalous "Mott-like" strong topological insulating state.