Numerical Study of the Pairing Correlation of the t-J Type Models

TL;DR

This study investigates the pairing correlations in t-J models, finding no long-range d-wave superconductivity in certain parameters, and re-evaluates the numerical method's validity across different models.

Contribution

It re-examines the monotonic behavior assumption of pairing correlations in t-J models using the power-Lanczos method across various geometries.

Findings

No long-range d-wave correlations for J/t ≤ 0.5 in 2D t-J model.

The power-Lanczos method's assumption of monotonicity is validated in 1D and ladder t-J models.

Method appears reliable for studying pairing correlations in these models.

Abstract

We reported that the pair-pair correlation function of the two-dimensional t-J model does not have long-range d-wave superconducting correlations in the interesting parameter range of $J/t \leq 0.5$. The power-Lanczos method is used under the assumption of monotonic behavior. This assumption has been well checked in the two-dimensional t-J and attractive Hubbard model. Here we re-examine this criterion of monotonic behavior of the pairing correlation function for the one-dimensional and two-leg t-J ladder where other accurate numerical results are available. The method seems to be working well.