Nernst effect as a signature of quantum fluctuations in quasi-one-dimensional superconductors

摘要

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. Assuming a weak Josephson coupling on the rungs, the off-diagonal Peltier coefficient (α_(xy)) and the Nernst effect are evaluated as functions of B and the temperature T. In this regime, the Nernst effect is found to exhibit a prominent peak close to the superconductor-insulator transition, which becomes progressively enhanced at low T. In addition, we derive a relation to the diamagnetic response α_(xy) = -M/T_0, where M is the equilibrium magnetization and T_0 a plasma energy in the superconducting legs.