Enhancement of Pairing Correlation by t' in the Two-Dimensional Extende d t-J Model

TL;DR

This study examines how next-nearest and third-nearest neighbor hopping terms influence superconductivity in the 2D extended t-J model, revealing that these terms enhance superconducting correlations in certain doping regions.

Contribution

It provides a comprehensive analysis using multiple methods showing the dual effect of t' and t" on superconductivity across doping levels.

Findings

Superconducting correlation is slightly suppressed by t' and t" in underdoped regions.

Superconducting correlation is greatly enhanced in optimal and overdoped regions.

Optimal T_c results from a balance of opposing effects of t' and t".

Abstract

We investigate the effects of the next-nearest-neighbor ($t'$) and the third-nearest-neighbor (t") hopping terms on superconductivity (SC) correlation in the 2D hole-doped extended t-J model based on the variational Monte-Carlo (VMC), mean-field (MF) calculation, and exact diagonalization (ED) method. Despite of the diversity of the methods employed, the results all point to a consistent conclusion: While the d-wave SC correlation is slightly suppressed by t' and t" in underdoped regions, it is greatly enhanced in the optimal and overdoped regions. The optimal T_c is a result upon balance of these two opposite trends.