Theoretical analysis of Cooper-pair phase fluctuations in underdoped cuprates: a spin-fluctuation exchange study

TL;DR

This paper provides a theoretical analysis of phase fluctuations in underdoped cuprates using spin-fluctuation exchange, explaining their impact on superconducting properties and transition temperatures.

Contribution

It introduces a comprehensive electronic theory to analyze phase fluctuations and their effects on superfluid density, transition temperatures, and spectral properties in underdoped cuprates.

Findings

Phase fluctuations significantly reduce $T_c$ in underdoped cuprates.

Superfluid density $n_s(T)$ and penetration depth $ au(x,T)$ are calculated.

Theoretical results align with experimental observations of $T_c$ suppression.

Abstract

We study Cooper-pair phase fluctuations in cuprate superconductors for a spin fluctuation pairing interaction. Using an electronic theory we calculate in particular for the underdoped cuprate superconductors the superfluid density $n_s(T)$, the superconducting transition temperature $T_c(x) \propto n_s$ below which phase coherent Cooper-pairs occur, and $T_c^{*}(x)$ where the phase incoherent Cooper-pairs disappear. Also we present results for the penetration depth $\lambda(x,T)$ and for the weak pseudogap temperature $T^{*}(x)$ at which a gap structure occurs in the spectral density. A Mei{\ss}ner effect is obtained only for $T < T_c$. We find that phase fluctuations become increasingly important in the underdoped regime and lead to a reduction of $T_c$ in good agreement with the experimental situation.