The two-orbital Hubbard model and the OSMT

TL;DR

This paper investigates the orbital selective Mott transition in a two-orbital Hubbard model using the Composite Operator Method, revealing how the transition depends on bandwidth ratios and interorbital interactions.

Contribution

It applies the Composite Operator Method to analyze the OSMT in a two-orbital Hubbard model, highlighting the role of bandwidths and interorbital interactions.

Findings

Clear signature of OSMT observed in density of states

Transition depends on the ratio of orbital bandwidths

Interorbital interaction influences the transition

Abstract

We analyze the two-orbital Hubbard model by means of the Composite Operator Method with the aim at studying the phenomenon of orbital selective Mott transition (OSMT). The model contains an interorbital interaction $U'$, in addition to the usual intraorbital one $U$. As warming-up approximation, we use a basis of two operators only, the Hubbard operators. The analysis of the density of states at the chemical potential as a function of the ratio between the bandwidths of the two orbitals shows the clear signature of an orbital selective Mott transition as expected.