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arXiv · 2312.08284

Unconventional correlated metallic behavior due to interorbital Coulomb interaction

N. Aucar Boidi·A. P. Kampf·K. Hallberg
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Abstract

We study the non-degenerate one dimensional two-orbital Hubbard model with interorbital Coulomb interaction. By means of the density-matrix renormalization group technique, we calculate the local single-particle density of states and the optical conductivity at zero temperature. We find that a finite interorbital Coulomb repulsion $V$ generates a new class of states within the Mott-Hubbard band which has a large weight of holon-doublon pairs, which we hence call the holon-doublon band (HDB). When $V$ is sufficiently large, the HDB specifies the gapless low-energy excitations, and the system becomes an unconventional correlated metal. Optical conductivity results resolve different metallic behaviors for zero and finite interaction $V$. Compared to the case without interorbital interaction, the conductivity is strongly reduced in the correlated holon-doublon metal for finite $V$. In addition, the absorption spectrum is dominated by the HDB, which is clearly distinguishable from the Mott-Hubbard band.

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N. Aucar Boidi, A. P. Kampf, K. Hallberg. 2023-12-13. Unconventional correlated metallic behavior due to interorbital Coulomb interaction. https://doi.org/10.1103/physrevb.109.085122

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