Unidirectional d-wave superconducting domains in the two-dimensional t-J model

TL;DR

This paper investigates the spontaneous formation of unidirectional modulated d-wave superconducting domains in the two-dimensional t-J model at 1/8 doping, inspired by experimental observations in high-T_c superconductors.

Contribution

It demonstrates the emergence of unidirectional charge and superconducting order in the t-J model, providing a theoretical basis for observed domain patterns in high-T_c materials.

Findings

Half-filled charge domains form along one crystal axis.

Modulated superconductivity with out-of-phase d-wave order parameters occurs.

Energies of modulated and uniform phases are nearly degenerate.

Abstract

Motivated by the recently observed pattern of unidirectional domains in high-T_c superconductors [Y. Kohsaka et al., Science 315, 1380 (2007)], we investigate the emergence of spontaneous modulations in the d-wave superconducting resonating valence bond phase using the t-J model at x=1/8 doping. Half-filled charge domains separated by four lattice spacings are found to form along one of the crystal axis leading to modulated superconductivity with out-of-phase d-wave order parameters in neighboring domains. Both renormalized mean-field theory and variational Monte Carlo calculations yield that the energies of modulated and uniform phases are very close to each other.