Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: Transport: Topological Insulators 1 (jointly with HL and MA)
TT 4.2: Vortrag
Montag, 26. März 2012, 09:45–10:00, H 3010
Interaction and trapping effects on a 2D topological insulator in an optical lattice. — •Daniel Cocks1, Peter P. Orth2, Michael Buchhold1, Stephan Rachel3, Karyn Le Hur4,3, and Walter Hofstetter1 — 1Institut für Theoretische Physik, Goethe-Universität Frankfurt — 2Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie — 3Department of Physics, Yale University, New Haven — 4Center for Theoretical Physics, École Polytechnique, Palaiseau
We investigate effects of interaction, disorder and trapping of a 2D system that exhibits topologically insulating phases in an optical square lattice using both real-space dynamical mean-field theory (R-DMFT) and analytical techniques. The tunability of this system allows for a large degree of freedom, and by adjusting the size of the magnetic unit cell, along with the strength of a spin-orbit coupling that does not preserve the Sz spin component and a staggered super-lattice potential, topologically non-trivial regions have been identified.
Using R-DMFT, we determine the interacting phase diagram as a function of Hubbard U. We observe interaction driven transitions between the topological and normal insulating phase, as well as dependence of transitions to magnetically ordered phases on the flux parameter. We also analyze trapping effects that are relevant to experimental conditions and identify ideal trapping potentials that preserve the topological phases. This system is realizable (Goldman et al. PRL 105, 255302, 2010) as an effective Hamiltonian by generating a synthetic non-Abelian gauge field on the surface of an atom chip.