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Minimal charge gap in the ionic Hubbard model

K. Pozgajcic·C. Gros
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Abstract

We study the ionic Hubbard model at temperature T=0 within the mean-field approximation, and show that the charge gap does not close completely at the ionic-band insulator to antiferromagnetic insulator transition, contrary to previous expectations. Furthermore, we find an intermediate phase for on-site repulsions $U>U_c$ for different lattices, and calculate the phase diagram for the ionic Hubbard model with alternating U, corresponding to a Cu-O lattice.

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K. Pozgajcic, C. Gros. 2003-09-16. Minimal charge gap in the ionic Hubbard model. https://doi.org/10.1103/physrevb.68.085106

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