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arXiv · 2605.24927

Strong Correlation Effect and In-gap State in the Doped Electron-Hole Two-Band Hubbard Model Based on the Dynamical Mean-Field Theory

Masashi Akiyama·Yusuke Inokuma·Yoshiaki Ono
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Abstract

We investigate the strong correlation effect in the spinless electron-hole two-band Hubbard model using the dynamical mean-field theory. At half filling, both the renormalization factor $Z$ and the number of conduction electrons (valence holes) $n_c$ decrease with increasing the interband Coulomb interaction $U$ down to $Z\sim 0.15$ and $n_c\sim 0.1$ for $U_c \sim \mbox{bandwidth}$ at which the first-order Lifshitz transition occurs from a correlated semimetal with a large effective mass $m^*/m=Z^{-1}$ to a band insulator with a finite gap due to the Hartree shift. A slight hole doping $x$ in the band insulator with a large $U>U_c$ yields a remarkable correlated semimetal with $Z\sim 0.1$ at $x\sim 0.01$, where in-gap states emerge above the valence band top and those weights increase with increasing $x$ together with the increase in $Z$ similar to the in-gap states observed in doped Mott insulators.

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Masashi Akiyama, Yusuke Inokuma, Yoshiaki Ono. 2026-05-24. Strong Correlation Effect and In-gap State in the Doped Electron-Hole Two-Band Hubbard Model Based on the Dynamical Mean-Field Theory. https://arxiv.org/abs/2605.24927

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