In-gap band in the one-dimensional two-orbital Kanamori-Hubbard model with inter-orbital Coulomb interaction

Abstract

We study the electronic spectral properties at zero temperature of the one-dimensional (1D) version of the degenerate two-orbital Kanamori Hubbard model (KHM), one of the well established frameworks to study transition metal compounds, using state-of-the-art numerical techniques based on the Density Matrix Renormalization Group. While the system is Mott insulating for the half-filled case, as expected for an interacting 1D system, we find interesting and rich structures in the single-particle density of states (DOS) for the hole-doped system. In particular, we find the existence of in-gap states which are pulled down to lower energies from the upper Hubbard band (UHB) with increasing the inter-orbital Coulomb interaction $V$. We analyze the composition of the DOS by projecting it onto different local excitations and we observe that for large dopings these in-gap excitations are formed mainly by inter-orbital holon-doublon (HD) states and their energies follow approximately the HD states in the atomic limit. We observe that the Hund interaction $J$ increases the width of the in-gap band, as expected from the two-particle fluctuations in the Hamiltonian. The observation of a finite density of states within the gap between the Hubbard bands for this extended 1D model indicates that these systems present a rich excitation spectra which could help us understand the microscopic physics behind multi-orbital compounds.

References in corpus (22)

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• Strong electronic correlations from Hund's coupling
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• Emergent low-energy bound states in the two-orbital Hubbard model
• Photoinduced Hund excitons in the breakdown of a two-orbital Mott insulator
• Doublon-holon excitations split by Hund's rule coupling within the orbital-selective Mott phase
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Cited by in corpus (8)

• Hund bands in spectra of multiorbital systems
• Precise ground state of multi-orbital Mott systems via the variational discrete action theory
• Emergence of electronic modes by doping Kondo insulators in the Kondo lattice and periodic Anderson models
• Low-energy interband Kondo bound states in orbital-selective Mott phases
• Unconventional correlated metallic behavior due to interorbital Coulomb interaction
• Observation of Two Cascading Screening Processes in an Iron-based Superconductor
• Quantitative determination of the orbital-selective Mott transition and quantum entanglement in the orbital-selective Mott phase
• Bad metal and negative compressibility transitions in a two-band Hubbard model