Evolution between two orbital-selective Mott phases driven by interorbital hopping

TL;DR

This study explores how interorbital hopping influences orbital selective Mott phases in a two-band system, revealing that the sign and magnitude of hopping can either enhance, suppress, or induce new OSMP regimes, with implications for related superconductors.

Contribution

The paper demonstrates the impact of interorbital hopping sign and magnitude on the evolution of OSMPs using dynamical mean-field theory, revealing new phases and behaviors not previously characterized.

Findings

Negative interorbital hopping enhances OSMP regimes.

Positive interorbital hopping narrows and can eliminate OSMP regions.

A new OSMP emerges at large positive interorbital hopping.

Abstract

The effect of interorbital hopping on the orbital selective Mottness in a two-band correlation system is investigated by using the dynamical mean-field theory with the Lanczos method as impurity solver. We construct the phase diagram of the two-orbital Hubbard model with interorbital hopping ($t_{12})$, where the orbital selective Mott phases (OSMP) show different evolution trends. We find that the negative interorbital hopping ($t_{12}<0$) can enhance the OSMP regime upon tuning the effective bandwidth ratio. On the contrary, for the cases with positive interorbital hopping ($t_{12}>0$), the OSMP region becomes narrow with the increase of orbital hybridization until it disappears. It is also shown that a new OSMP emerges for a large enough positive interorbital hopping, owing to the role exchange of wide and narrow effective orbitals caused by the large $t_{12}$. Our results are also applicable to the hole-overdoped Ba$_2$CuO$_{4-\delta}$ superconductor, which is an orbital-selective Mott compound at half-filling.