Superconductivity of the One-Dimensional d-p Model with p-p transfer

TL;DR

This paper investigates how the transfer energy between oxygen sites influences superconductivity in a one-dimensional Cu-O chain model, revealing conditions that enhance charge susceptibility and flux quantization.

Contribution

It introduces a detailed numerical analysis of the one-dimensional d-p model, highlighting the role of p-p transfer energy in superconductivity and flux quantization phenomena.

Findings

t_{pp} increases charge susceptibility and K_{ρ}

Anomalous flux quantization occurs for K_{ρ}>1

Superconducting regions identified in phase diagram

Abstract

Using the numerical diagonalization method, we investigate the one-dimensional $d$-$p$ model, simulating a Cu-O linear chain with strong Coulomb repulsions. Paying attention to the effect of the transfer energy $t_{pp}$ between the nearest neighbor oxygen-sites, we calculate the critical exponent of correlation functions $K_{\rho}$ based on the Luttinger liquid relations and the ground state energy $E_0(\phi)$ as a function of an external flux $\phi$. We find that the transfer $t_{pp}$ increases the charge susceptibility and the exponent $K_{\rho}$ in cooperation with the repulsion $U_{d}$ at Cu-site. We also show that anomalous flux quantization occurs for $K_{\rho}>1$. The superconducting region is presented on a phase diagram of $U_{d}$ vs. $t_{pp}$ plane.