Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 48: CE: Metal-Insulator Transition 2

TT 48.7: Talk

Thursday, March 17, 2011, 12:15–12:30, HSZ 105

Orbital selective phase transitions observed in dynamical cluster approximation calculations — Hunpyo Lee¹, Yu-Zhong Zhang², •Harald O. Jeschke¹, and Roser Valentí¹ — ¹Institut für Theoretische Physik, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany — ²Department of Physics, Tongji University, Shanghai 200092, PR China

We study a two-orbital Hubbard model with unequal bandwidths on the square lattice using the dynamical cluster approximation (DCA) based on the hybridization expansion continuous-time quantum Monte Carlo method. In the case of four site clusters, the competition between Slater and Mott physics leads to orbital selective phases for intermediate values of the interaction strength. We also investigate a two-orbital Hubbard model with equal bandwidths where we allow one orbital to have an antiferromagnetic solution (AF orbital) while we constrain the other orbital to be paramagnetic (PM orbital). We find an interesting phase diagram with orbital selective phases that are caused by the different magnetic states in the two orbitals: As function of the interaction strength, the PM orbital undergoes a transition from a Fermi liquid to a Mott insulator through an intermediate non-Fermi liquid phase while the AF orbital shows a transition from a Fermi liquid to an antiferromagnetic insulator through an intermediate antiferromagnetic metallic phase.