Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 19: Transport: Topological Insulators 2 (jointly with TT, MA)

HL 19.5: Vortrag

Montag, 26. März 2012, 16:00–16:15, H 3005

Quantum phase transitions in the Kane-Mele-Hubbard model — Martin Hohenadler¹, Zi Yang Meng², •Thomas C. Lang³, Stefan Wessel³, Alejandro Muramatsu⁴, and Fakher F. Assaad¹ — ¹Universität Würzburg, Würzburg, Germany — ²Louisiana State University, Baton Rouge, USA — ³RWTH Aachen, Aachen, Germany — ⁴Universität Stuttgart, Stuttgart, Germany

We study the two-dimensional Kane-Mele-Hubbard model at half filling by means of quantum Monte Carlo simulations. We present a refined phase boundary for the quantum spin liquid. The topological insulator at finite Hubbard interaction strength is adiabatically connected to the groundstate of the Kane-Mele model. In the presence of spin-orbit coupling, magnetic order at large Hubbard U is restricted to the transverse direction. The transition from the topological band insulator to the antiferromagnetic Mott insulator is in the universality class of the three-dimensional XY model. The numerical data suggest that the spin liquid to topological insulator and spin liquid to Mott insulator transitions are both continuous.