A toy model for the pseudogap state of cuprates

TL;DR

This paper introduces a simplified model to study the pseudogap state in cuprate superconductors, focusing on pre-formed pairs and their spin-driven spatial organization, revealing a transition to a spin-density wave phase.

Contribution

It presents a novel toy model using mean-field theory to analyze short-range correlations and the emergence of long-range order in the pseudogap state of cuprates.

Findings

Short-range correlations increase below transition temperature

Long-range spin-density wave order develops

Heat capacity shows characteristic behavior at transition

Abstract

A toy model is developed to capture "dance of pre-formed pairs" in the pseudogap state of high temperature cuprate superconductors. The model is a crude description of a hypothetical situation in which spin-driven spatial organization of the pre-formed pairs is analyzed. Within a mean-field theory (a slight generalization of Bragg-Williams theory) we examined the behaviour of heat capacity and an "order parameter" which captures the short range correlations between the pre-formed pairs. Below a transition temperature these short range correlations enhance and leads to a long range order (spin-density wave). This is examined through the breakdown of statistical independence.