Thermoelectric effects in superconductors

TL;DR

This paper clarifies that thermoelectric effects in superconductors are mediated by the Bernoulli potential and supercurrents, challenging the belief that such effects are negligible in these materials.

Contribution

It introduces a new understanding of thermoelectric effects in superconductors via the Bernoulli potential and proposes contactless measurement methods.

Findings

Thermoelectric effects in superconductors are explained by the Bernoulli potential.

Supercurrents cancel quasiparticle diffusion currents, enabling thermoelectric effects.

Contactless measurement techniques are suggested for these effects.

Abstract

It is widely believed that temperature gradient does not induce electric field in the superconductor and consequently that thermoelectric effects do not exist, or are negligible in these materials. This statement is correct only as far as effective electric field or gradient of the electrochemical potential is concerned. In normal metals temperature gradient generates effective electric field, which nulls out thermally induced diffusion current. In superconductor the diffusion current of quasiparticles is canceled a counterflow of supercurrent. Superconducting current induces the true electric field, which can be approximated by gradient of the screened Bernoulli potential. It explains familiar giant thermomagnetic flux observed in superconducting thermocouples. Contactless measurements of thermoelectric effects are suggested.