Vortex-pair unbinding in the normal state of two-dimensional, short coherence-length superconductors

TL;DR

This paper investigates vortex-pair unbinding in the normal state of 2D superconductors with short coherence length, revealing XY critical scaling and its implications for pseudogap phenomena in underdoped cuprates.

Contribution

It demonstrates that the attractive Hubbard model exhibits XY critical scaling in the normal state, highlighting the role of vortex unbinding in pseudogap behavior.

Findings

XY critical scaling observed in correlation length and pair susceptibility

Critical regime extends beyond 5 times T_KTB

Vortex-pair unbinding influences pseudogap phenomena

Abstract

We study the superconducting transition in the attractive Hubbard model in two dimensions using the self-consistent $T$-matrix approximation. We demonstrate that for large system sizes, this approximate method produces XY critical scaling in the correlation length and pair susceptibility. For the parameters we investigate, the critical regime is quite large, extending beyond 5 times $\TKTB$. We discuss the role of vortex-pair unbinding in the normal state in the context of pseudogap behaviour and the relevance to the physics of underdoped cuprates.