The Nernst effect in high-$T_c$ superconductors

TL;DR

This paper presents evidence that vortex excitations persist above the critical temperature in high-$T_c$ cuprates, supporting a phase-disordering scenario where superfluidity is destroyed by thermally-created vortices, extending into the pseudogap state.

Contribution

It provides experimental evidence supporting the phase-disordering model of superconductivity loss in high-$T_c$ cuprates, highlighting vortex survival above $T_c$.

Findings

Large Nernst signal observed above $T_c$

Vortex excitations survive in the pseudogap regime

Supports phase-disordering scenario for superconductivity loss

Abstract

The observation of a large Nernst signal $e_N$ in an extended region above the critical temperature $T_c$ in hole-doped cuprates provides evidence that vortex excitations survive above $T_c$. The results support the scenario that superfluidity vanishes because long-range phase coherence is destroyed by thermally-created vortices (in zero field), and that the pair condensate extends high into the pseudogap state in the underdoped (UD) regime. We present a series of measurements to high fields $H$ which provide strong evidence for this phase-disordering scenario.