Effects of quasiparticle ambipolarity on the Nernst effect in underdoped cuprate superconductors

TL;DR

This paper investigates how quasiparticle ambipolarity influences the Nernst effect in the normal state of underdoped cuprate superconductors, predicting a temperature-dependent peak linked to Fermi surface pockets.

Contribution

It introduces an ambipolar d-density wave model to explain the Nernst effect and predicts a specific peak behavior and sign consistent with recent experimental observations.

Findings

Prediction of a Nernst coefficient peak below pseudogap temperature

The sign of the Nernst effect matches that of mobile vortices in superconductors

Dominance of electron pockets at low temperatures explains experimental data

Abstract

We consider the Nernst effect in the normal state of the underdoped cuprate superconductors, where recent quantum oscillation experiments have indicated the existence of Fermi surface pockets and quasiparticle ambipolarity in the excitation spectrum. Using an ambipolar d-density wave model for the pseudogap, we predict a peak in the Nernst coefficient with decreasing temperature below the pseudogap temperature. The existence of the peak and its sign, which we predict to be the same as that due to mobile vortices in a superconductor, result from the dominance of the electron pocket at low temperatures, as has been observed in recent Hall experiments.