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Dynamical mean-field study of the ionic Hubbard model at finite temperatures (Talk/poster #: to be completed by the Organizer) Aaram J. Kim1, Moo Young Choi1 and Gun Sang Jeon 2 1 Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747, Korea 2 Department of Physics, Ewha Womans University, Seoul 120-750, Korea *Email of Presenting Author: [email protected] We present the results of an extensive study on finite-temperature phase transitions in the infinite-dimensional ionic Hubbard model. We use the dynamical mean-field theory combined with continuous-time quantum Monte Carlo method. The nontrivial metallic phase between band and Mott insulating phases, which is induced by the competition between the staggered lattice potential and the local Coulomb interaction, is found to survive at finite temperatures. While the system undergoes a crossover between band insulator and metallic phase at all temperature studied, a first-order transition occurs from metal to Mott insulator below the critical temperature. As the strength of the staggered lattice potential increases, the metallic region shrinks gradually in the phase diagram and the critical temperature rises. In the strong-coupling limit, a small but finite region of a metallic phase still persists and the critical temperature converges to a certain value.
