Hannover 2013 – scientific programme
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A: Fachverband Atomphysik
A 29: Poster: Ultra-cold atoms, ions and BEC (with Q)
A 29.19: Poster
Wednesday, March 20, 2013, 16:00–18:30, Empore Lichthof
Topological Insulators in Optical Lattices: interaction and trapping — •Daniel Cocks1, Peter Orth2, Michael Buchhold1, Stephan Rachel3, Karyn Le Hur4, and Walter Hofstetter1 — 1Institut für Theoretische Physik, Goethe Universität, Frankfurt — 2Institut für Theorie der Kondensierten Materie, Karlsruhe Institut für Technologie — 3Institut für Theoretische Physik, Technische Universität Dreseden — 4Center for Theoretical Physics, École Polytechnique, Palaiseau
We investigate effects of interaction and trapping in a 2D system to be realised in experiment (Goldman et al. PRL 105, 255302, 2010) that exhibits topologically insulating phases in an optical square lattice, using both real-space dynamical mean-field theory (R-DMFT) and analytical techniques. This system includes a flux term, which emulates a spin-dependent magnetic field, a Rashba/Dresselhaus-like spin-orbit term, which introduces non-Abelian behavior, and a staggered super-lattice potential, which introduces non-trivial topology at half-filling.
We investigate with R-DMFT the robustness of the topological phases for weak interaction, and transitions to magnetic order at strong interaction. We demonstrate a critical dependence on the number of Dirac points. As well, we derive and analyze the corresponding spin-Hamiltonian and show that the competition of flux and Rashba-like spin-orbit couplings produce non-trivial spiral-like orders. We also consider the effects of trapping on the visibility of edge states, and show that new interesting features arise when smooth trapping is present.