A dynamical mean-field study of orbital-selective Mott phase enhanced by next-nearest neighbor hopping

TL;DR

This study uses dynamical mean-field theory to explore how next-nearest neighbor hopping enhances the orbital-selective Mott transition in a two-orbital Hubbard model, revealing that NNN hopping significantly extends the OSMT region.

Contribution

It demonstrates that NNN hopping breaks particle-hole symmetry and promotes OSMT, providing new insights into the role of hopping terms in orbital-selective Mott physics.

Findings

NND hopping extends the OSMT region.

Broken particle-hole symmetry benefits OSMT.

Hund's coupling promotes OSMT by suppressing orbital fluctuations.

Abstract

The dynamical mean-field theory is employed to study the orbital-selective Mott transition (OSMT) of the two-orbital Hubbard model with nearest neighbor hopping and next-nearest neighbor (NNN) hopping. The NNN hopping breaks the particle-hole symmetry at half filling and gives rise to an asymmetric density of states (DOS). Our calculations show that the broken symmetry of DOS benefits the OSMT, where the region of the orbital-selective Mott phase significantly extends with the increasing NNN hopping integral. We also find that Hund's rule coupling promotes OSMT by blocking the orbital fluctuations, but the influence of NNN hopping is more remarkable.