FFLO oscillations and magnetic domains in the Hubbard model with off-diagonal Coulomb repulsion

TL;DR

This paper investigates how non-zero magnetization affects the superconducting ground state of a one-dimensional Hubbard model with correlated hopping, revealing FFLO oscillations, phase separation, and magnetic insulator phases.

Contribution

It demonstrates the impact of off-diagonal Coulomb repulsion on superconductivity, phase separation, and magnetic ordering in the Hubbard model with correlated hopping.

Findings

FFLO oscillations appear in pair correlations for certain parameters

Macroscopic phase separation occurs driven by kinetic energy at specific magnetizations

High magnetization leads to a ferrimagnetic insulating state

Abstract

We observe the effect of non-zero magnetization m onto the superconducting ground state of the one dimensional repulsive Hubbard model with correlated hopping X. For t/2 < X < 2t/3, the system first manifests Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) oscillations in the pair-pair correlations. For m = m1 a kinetic energy driven macroscopic phase separation into low-density superconducting domains and high-density polarized walls takes place. For m > m2 the domains fully localize, and the system eventually becomes a ferrimagnetic insulator.