Enhanced d_{x^2-y^2} pairing correlations in the two-leg Hubbard ladder

TL;DR

This study investigates how pairing correlations in the two-leg Hubbard ladder are affected by various parameters, revealing enhancement near specific band alignments and providing insights through spectral and magnetic analyses.

Contribution

It demonstrates that pairing correlations are enhanced when certain quasiparticle bands are near the Fermi level, using advanced numerical simulations to explore parameter dependence.

Findings

Pairing correlations are enhanced near specific band alignments.

Spectral weight and antiferromagnetic correlations explain this behavior.

Results are obtained through density matrix renormalization group and Monte Carlo simulations.

Abstract

The two-leg Hubbard ladder is characterized by the ratio of the inter- to intra-leg hopping t_perp/t, the relative interaction strength U/t and the electron filling. Here, using density matrix renormalization group and Monte Carlo simulations, we examine the dependence of the pairing correlations on these parameters. We find that the pairing correlations are enhanced when the top of the bonding quasiparticle band and the bottom of the antibonding band are near the Fermi level. We present results on the single-particle spectral weight and the antiferromagnetic correlations in order to explain this behavior.