Wednesday, November 14, 2012

1211.3059 (Jan Carl Budich et al.)

Fluctuation driven topological Hund insulator    [PDF]

Jan Carl Budich, Björn Trauzettel, Giorgio Sangiovanni
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.
View original: http://arxiv.org/abs/1211.3059

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