Nernst Effect as a Signature of Quantum Fluctuations in Quasi-1D Superconductors

TL;DR

This paper investigates the Nernst effect as an indicator of quantum fluctuations near the superconductor-insulator transition in a two-leg Josephson ladder, revealing a peak in the Nernst response linked to quantum criticality.

Contribution

It introduces a model connecting quantum superconducting fluctuations with the Nernst effect and derives a relation between the Nernst response and diamagnetic magnetization.

Findings

Nernst effect peaks near the superconductor-insulator transition

Peak in Nernst effect becomes more pronounced at lower temperatures

Derived a relation between Nernst response and diamagnetic magnetization

Abstract

We study a model for the transverse thermoelectric response due to quantum superconducting fluctuations in a two-leg Josephson ladder, subject to a perpendicular magnetic field B and a transverse temperature gradient. The off-diagonal Peltier coefficient (\alpha_{xy}) and the Nernst effect are evaluated as functions of B and the temperature T. The Nernst effect is found to exhibit a prominent peak close to the superconductor-insulator transition (SIT), which becomes progressively enhanced at low T. In addition, we derive a relation to diamagnetic response: \alpha_{xy}= -M/T_0, where M is the equilibrium magnetization and T_0 a plasma energy in the superconducting legs.