Thermoelectric effects in superconductors

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 by 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.