Thermopower of a superconducting single-electron transistor

TL;DR

This paper develops a linear-response theory to analyze how the thermopower in a superconducting single-electron transistor varies with superconducting gap size and conductance oscillations, revealing qualitative changes from normal devices.

Contribution

It introduces a theoretical framework for thermopower in superconducting single-electron transistors, highlighting the impact of superconducting gap on thermoelectric behavior.

Findings

Thermopower oscillates with conductance periodicity.

Thermopower is highly sensitive to the superconducting gap.

Shape of thermopower curve changes qualitatively with gap size.

Abstract

We present a linear-response theory for the thermopower of a single-electron transistor consisting of a superconducting island weakly coupled to two normal-conducting leads (NSN SET). The thermopower shows oscillations with the same periodicity as the conductance and is rather sensitive to the size of the superconducting gap. In particular, the previously studied sawtooth-like shape of the thermopower for a normal-conducting single-electron device is qualitatively changed even for small gap energies.