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TT: Fachverband Tiefe Temperaturen

TT 15: Correlated Electrons: Metal-Insulator Transition 2

TT 15.9: Vortrag

Dienstag, 24. März 2009, 12:00–12:15, HSZ 301

Phase diagram of the SU(N) Hubbard-Heisenberg model on the honeycomb lattice — •Thomas C. Lang¹, Zi Yang Meng², Stefan Wessel², Fakher F. Assaad¹, and Alejandro Muramatsu² — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — ²Institut für Theoretische Physik III, Universität Stuttgart, Germany

We investigate the phase diagram of the half-filled SU(N) Hubbard-Heisenberg model on the honeycomb lattice in the self-adjoint totally antisymmetric representation. By means of the projective (T = 0) quantum Monte Carlo method we simulate the model on lattices ranging up to L = 15. For U=0 and in the quantum limit, N=2, decreasing t/J triggers a quantum phase transition from semi-metal to an antiferromagnetic-insulator with no apparent intermediate phase. With increasing symmetry N the Hubbard-Heisenberg model exhibits purely paramagnetic phases. Our aim is to study in detail the phase diagram as a function of N from the quantum limit to the saddle point N→∞.