Thermoelectric generation of charge imbalance at a superconductor-normal metal interface

Journal Article · Wed Jul 01 04:00:00 EDT 1981 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00115081· OSTI ID:1134736

Van Harlingen, D. J.

The thermoelectric voltage produced across a superconductor-normal metal-superconductor (SNS) sandwich by an applied heat current has been measured in Pb-Cu-PbBi and In-Al-Sn as a function of temperature. The observed divergence of the thermoelectric voltage near T{sub c} is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length {lambda}{sub Q*}. The charge imbalance is generated by thermoelectrically driven quasiparticle currents in the superconductor. It contributes a voltage per unit heat power given by V{sub s}/P = {lambda}{sub Q*}S/{kappa}A, where A is the sample cross-sectional area, and S and {kappa} are the thermopower and the thermal conductivity of quasiparticles in the superconductor. For Pb and In, we find the measured thermopower in the superconducting state to be slowly-varying with temperature near T{sub c} and consistent in magnitude with normal state values. This result is in agreement with theoretical predictions of thermoelectric effects in superconductors but contrary to previous experimental results obtained by other methods.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Materials Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1134736
• Report Number(s): LBL-12029
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 1-2 Vol. 44; ISSN 0022-2291
• Publisher: Plenum Press
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY