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arXiv · 1804.07969

Quantum Phase transition in the two dimensional ionic-Hubbard model

A. Shahbazy·M. Ebrahimkhas
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Abstract

We employ the dynamical mean field approximation to study the effects of ionic potential ($Δ$) on the square lattice Hubbard model. At half-filling when the staggered potential ($Δ$) dominates the on-site Hubbard interaction ($U$), the system is in the band insulator phase. We find that competition between $U$ and $Δ$ can suppress the gap to zero and leading to an intermediate metallic region. At the large-$U$ limit, we identify a Mott insulator phase where the gap opens again and increases upon increasing the Hubbard interaction U. For $U\leq 9t$ and $Δ\approx 0$ the phase of the system is metallic, but for larger $U$ the system is in the Mott insulator phase.

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A. Shahbazy, M. Ebrahimkhas. 2018-08-20. Quantum Phase transition in the two dimensional ionic-Hubbard model. https://doi.org/10.1016/j.cjph.2019.01.013

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