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Can correlations drive a band insulator metallic?

Arti Garg·H. R. Krishnamurthy·Mohit Randeria
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Abstract

We analyze the effects of the on-site Coulomb repulsion U on a band insulator using dynamical mean field theory (DMFT). We find the surprising result that the gap is suppressed to zero at a critical Uc1 and remains zero within a metallic phase. At a larger Uc2 there is a second transition from the metal to a Mott insulator, in which the gap increases with increasing U. These results are qualitatively different from Hartree-Fock theory which gives a monotonically decreasing but non-zero insulating gap for all finite U.

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Arti Garg, H. R. Krishnamurthy, Mohit Randeria. 2005-11-14. Can correlations drive a band insulator metallic?. https://doi.org/10.1103/physrevlett.97.046403

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