Jan Carl Budich, Ronny Thomale, Gang Li, Manuel Laubach, Shou-Cheng Zhang
We investigate the role of quantum fluctuations in topological quantum phase transitions of quantum spin Hall insulators and quantum anomalous Hall insulators. Employing the variational cluster approximation to obtain the single-particle Green's function of the interacting many-body system, we characterize different phases by direct calculation of the recently proposed topological order parameter for interacting systems. We illustrate the influence of quantum fluctuations on the quantum spin Hall to Mott insulator transition in several models. In particular, we relate the change of the topological order parameter to the frequency domain winding number of the system which provides a signature of interaction effects beyond band structure renormalization. Furthermore, we propose a general mechanism by which a topological quantum phase transition can be driven by the divergence of the self-energy induced by interactions.
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http://arxiv.org/abs/1203.2928
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