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arXiv · 1604.05851

Topological Insulators from Electronic Superstructures

Yusuke Sugita·Yukitoshi Motome
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Abstract

The possibility of realizing topological insulators by spontaneous formation of electronic superstructure is theoretically investigated in a minimal two-orbital model including both the spin-orbit coupling and electron correlations on a triangular lattice. Using the mean-field approximation, we show that the model exhibits several different types of charge ordered insulators, where the charge disproportionation forms a honeycomb or kagome superstructure. We find that the charge ordered insulators in the presence of strong spin-orbit coupling can be topological insulators showing quantized spin Hall conductivity. Their band gap is dependent on electron correlations as well as the spin-orbit coupling, and even vanishes with showing the massless Dirac dispersion at the transition to a trivial charge ordered insulator. Our results suggest a new route to realize and control topological states of quantum matter by the interplay between the spin-orbit coupling and electron correlations.

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Yusuke Sugita, Yukitoshi Motome. 2016-06-20. Topological Insulators from Electronic Superstructures. https://doi.org/10.7566/jpsj.85.073709

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