Unidirectional Charge Instability of the d-wave RVB Superconductor

TL;DR

This paper investigates the energy differences between uniform and inhomogeneous d-wave RVB superconducting phases, suggesting that minor perturbations could induce inhomogeneous states as observed experimentally.

Contribution

It demonstrates through theoretical calculations that inhomogeneous superconducting phases are energetically competitive with uniform phases in the t-J model.

Findings

Inhomogeneous and uniform phases have very close energies.

Small perturbations can favor inhomogeneous superconducting states.

Results align with recent experimental observations.

Abstract

Starting from a uniform d-wave superconducting phase we study the energy cost due to imposed unidirectional defects with a vanishing pairing amplitude. Both renormalized mean-field theory and variational Monte Carlo calculations within the t-J model yield that the energies of inhomogeneous and uniform phases are very close to each other. This suggests that small perturbations in the microscopic Hamiltonian, might lead to inhomogeneous superconducting phases in real materials as observed in recent scanning tunneling microscopy on Ca_{2-x}Na_xCuO_2Cl_2.