Effects of Hund's coupling on the Mott transition in multiorbital systems

摘要: We study the phase transitions in the two-orbital Hubbard model having different orbital bandwidths, with emphasis on the effects of the Ising-type Hund's coupling. Within the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method, we confirm the existence of a non-Fermi-liquid for intermediate interactions. In contrast to the paradigmatic Mott transition in the single-band Hubbard model, a metallic phase is dominant over a localized Mott insulator at finite temperatures, resulting in the opposite slope of the phase boundary. We also investigate how the nature of the Mott transition between the non-Fermi liquid and the Mott insulator is affected by the variations in the Hund's coupling strength.