Half-filled stripes in the t-t'-U Hubbard model

TL;DR

This study uses a Hartree-Fock approach to analyze stripe phases in the extended Hubbard model, revealing how negative next-nearest-neighbor hopping influences hole distribution and stripe stability, especially relevant for YBa2Cu3O6+δ.

Contribution

It demonstrates that negative t'/t ratios promote stripe order and hole redistribution, providing insights into the kinetic energy gains in high-temperature superconductor models.

Findings

Negative t'/t expels holes from antiferromagnetic domains.

Half-filled stripes optimize kinetic energy gain.

Stripe phases dominate around t'/t ≈ -0.3 for YBa2Cu3O6+δ.

Abstract

Using a self-consistent Hartree-Fock approximation we investigate the relative stability of various stripe phases in the extended $t$-$t'$-$U$ Hubbard model. One finds that a negative ratio of next- to nearest-neighbor hopping $t'/t<0$ expells holes from antiferromagnetic domains and reinforces the stripe order. Therefore the half-filled stripes not only accommodate holes but also redistribute them so that the kinetic energy is gained, and these stripes take over in the regime of $t'/t\simeq -0.3$ appropriate for YBa$_2$Cu$_3$O$_{6+\delta}$.