Metal-insulator transition in the hybridized two-orbital Hubbard model revisited

TL;DR

This study investigates the metal-insulator transition in a two-orbital Hubbard model with hybridization and crystal-field effects, revealing how orbital mixing influences electronic states and quasiparticle behavior.

Contribution

It provides a detailed numerical analysis of the two-orbital Hubbard model with hybridization, highlighting the impact on the density of states and quasiparticle peaks.

Findings

Orbital mixing induces finite density states at the Fermi energy in both orbitals.

Doped bands exhibit exponential quasiparticle peaks with Hubbard interaction U.

Hybridization always results in metallic behavior in at least one orbital.

Abstract

In this work we study the two-orbital Hubbard model on a square lattice in the presence of hybridization between nearest-neighbor orbitals and a crystal-field splitting. We use a highly reliable numerical technique based on the density matrix renormalization group to solve the dynamical mean field theory self-consistent impurity problem. We find that the orbital mixing always leads to a finite local density states at the Fermi energy in both orbitals when at least one band is metallic. When one band is doped, and the chemical potential lies between the Hubbard bands in the other band, the coherent quasiparticle peak in this orbital has an exponential behavior with the Hubbard interaction $U$.