Pair correlation functions in one-dimensional correlated-hopping models

TL;DR

This paper studies ground-state properties of two correlated-hopping electron models, revealing how pairing and superconducting correlations depend on interaction parameters through numerical analysis.

Contribution

It provides a comparative numerical analysis of the Hirsch and Bariev models, highlighting differences in superconducting correlations based on bond-charge interactions.

Findings

Pairing is favored in certain parameter ranges.

Superconducting correlations are suppressed in the Hirsch model beyond a critical repulsion.

Numerical results are obtained using the Lanczos technique on small clusters.

Abstract

We investigate ground-state properties of two correlated-hopping electron models, the Hirsch and the Bariev model. Both models are of recent interest in the context of hole superconductivity. Applying the Lanczos technique to small clusters, we numerically determine the binding energy, the spin gaps, correlation functions, and other properties for various values of the bond-charge interaction parameter. Our results for small systems indicate that pairing is favoured in a certain parameter range. However, in contrast to the Bariev model, superconducting correlations are suppressed in the Hirsch model, for a bond-charge repulsion larger than a critical value.