The Nernst effect from fluctuating pairs in the pseudogap phase

TL;DR

This paper investigates the large Nernst effect observed in cuprates above the superconducting transition, proposing that vertex corrections due to the pseudogap explain the experimental data better than Gaussian fluctuations alone.

Contribution

It introduces a vertex correction to gaussian fluctuation theory accounting for the pseudogap, improving the explanation of the Nernst signal in underdoped cuprates.

Findings

Vertex correction aligns theory with experimental data

Gaussian fluctuations insufficient for underdoped cuprates

Pseudogap significantly influences Nernst effect

Abstract

The observation of a large Nernst signal in cuprates above the superconducting transition temperature has attracted much attention. A potential explanation is that it originates from superconducting fluctuations. Although the Nernst signal is indeed consistent with gaussian fluctuations for overdoped cuprates, gaussian theory fails to describe the temperature dependence seen for underdoped cuprates. Here, we consider the vertex correction to gaussian theory resulting from the pseudogap. This yields a Nernst signal in good agreement with the data.