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TT: Fachverband Tiefe Temperaturen

TT 67: Topological Insulators 5 (jointly with DS, HL, MA, and O)

TT 67.7: Vortrag

Freitag, 15. März 2013, 11:00–11:15, H18

Fluctuation driven topological Hund insulator — •Jan Carl Budich¹, Bjoern Trauzettel², and Giorgio Sangiovanni² — ¹Department of Physics, Stockholm University, Se-106 91 Stockholm, Sweden — ²Institute for theoretical physics and astrophysics, 97074 Würzburg, Germany

We investigate in the framework of dynamical mean field theory a two-band Hubbard model based on the Bernevig-Hughes-Zhang Hamiltonian describing the quantum spin Hall (QSH) effect in HgTe quantum wells. In the presence of interaction, we find that a system with topologically trivial non-interacting parameters can be driven into a QSH phase at finite interaction strength by virtue of local dynamical fluctuations. For very strong interaction, the system reenters a trivial insulating phase by going through a Mott transition. We obtain the phase diagram of our model by direct calculation of the bulk topological invariant of the interacting system in terms of its single particle Green’s function.