Novel subbands in the doped two-orbital Kanamori-Hubbard model

TL;DR

This paper uses advanced computational methods to analyze the electronic structure of a key model for strongly correlated materials, revealing new subband features induced by doping and Hund's coupling.

Contribution

It introduces detailed spectral function calculations of the doped two-orbital Kanamori-Hubbard model using a highly optimized DMFT with DMRG, uncovering novel in-gap subbands and their origins.

Findings

Emergence of a novel holon-doublon in-gap subband split by Hund's coupling

Splitting of the lower Hubbard band into a coherent peak and evolving subband

Excellent agreement between response functions and atomic limit energies

Abstract

We calculate and resolve with unprecedented detail the local density of states (DOS) and momentum-dependent spectral functions at zero temperature of one of the key models for strongly correlated electron materials, the degenerate two-orbital Kanamori-Hubbard model, by means of a highly optimized Dynamical Mean Field Theory which uses the Density Matrix Renormalization Group as the impurity solver. When the system is hole doped, and in the presence of a finite interorbital Coulomb interaction we find the emergence of a novel holon-doublon in-gap subband which is split by the Hund's coupling. We also observe new interesting features in the DOS like the splitting of the lower Hubbard band into a coherent narrowly dispersing peak around the Fermi energy, and another subband which evolves with the chemical potential. We characterize the main transitions giving rise to each subband by calculating the response functions of specific projected operators and comparing with the energies in the atomic limit, obtaining excellent agreement. The detailed results for the spectral functions found in this work pave the way to study with great precision the microscopic quantum behavior in correlated materials.