Phase Diagram of the Extended Hubbard Model with Correlated Hopping Interaction

TL;DR

This paper maps the phase diagram of a one-dimensional extended Hubbard model with correlated hopping, revealing various insulating, metallic, and superconducting phases influenced by interaction parameters.

Contribution

It provides the first comprehensive phase diagram of the model including correlated hopping effects using continuum-limit field theory.

Findings

Identification of bond-ordered phases linked to Peierls instability for positive T*

Discovery of staggered magnetization on bonds for negative T*

Mapping of insulating, metallic, and superconducting phases across parameter space

Abstract

A one-dimensional model of interacting electrons with on-site $U$, nearest-neighbor $V$, and correlated-hopping interaction $T^{\ast}$ is studied at half-filling using the continuum-limit field theory approach. The ground state phase diagram is obtained for a wide range of coupling constants. In addition to the insulating spin- and charge-density wave phases for large $U$ and $V$, respectively, we identify bond-located ordered phases corresponding to an enhanced Peierls instability in the system for $T^\ast>0$, $|U-2V|<8T^\ast/\pi$ and to a staggered magnetization located on bonds between sites for $T^\ast<0$, $|U-2V|<8|T^\ast|/\pi$. The general ground state phase diagram including insulating, metallic, and superconducting phases is discussed.