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Spectral-weight function of the ionic Hubbard model

M. C. Refolio·J. M. Lopez Sancho·J. Rubio
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Abstract

The one-electron spectral-weight function of the half-filled ionic Hubbard model is calculated by means of Quantum Monte Carlo. A metallic regimen occurs between two values of the coupling constant (Hubbard U) U1 < U2 . The system is a band insulator below U1, and an increasingly antiferromagnetic (AF) insulator above U2 evolving into a Mott insulator as U tends to infinity . The intermediate regimen which is both AF and dimerized, is caused by a two-peak structure at k = 0,5 pi (the Fermi surface). As U increases both peaks approach each other, overlap, and separate again, the system becoming metallic in the overlap region.

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M. C. Refolio, J. M. Lopez Sancho, J. Rubio. 2002-10-21. Spectral-weight function of the ionic Hubbard model. https://arxiv.org/abs/cond-mat/0210462

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