Issue
EPL
Volume 86, Number 2, April 2009
Article Number 27007
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/86/27007
Published online 06 May 2009
EPL, 86 (2009) 27007
DOI: 10.1209/0295-5075/86/27007

Fluctuations of the superconducting order parameter as an origin of the Nernst effect

K. Michaeli1 and A. M. Finkel'stein1, 2

1   Department of Condensed Matter Physics, The Weizmann Institute of Science - Rehovot 76100, Israel
2   Department of Physics, Texas A&M University - College Station, TX 77843-4242, USA

karen.michaeli@weizmann.ac.il

received 16 January 2009; accepted in final form 31 March 2009; published April 2009
published online 6 May 2009

Abstract
We show that the strong Nernst signal observed recently in amorphous superconducting films far above the critical temperature is caused by the fluctuations of the superconducting order parameter. We demonstrate a striking agreement between our theoretical calculations and the experimental data at various temperatures and magnetic fields. Besides, the Nernst effect is interesting not only in the context of superconductivity. We discuss some subtle issues in the theoretical study of thermal phenomena that we have encountered while calculating the Nernst coefficient. In particular, we explain how the Nernst theorem (the third law of thermodynamics) imposes a strict constraint on the magnitude of the Nernst effect.

PACS
72.10.Bg - General formulation of transport theory.
73.50.Lw - Thermoelectric effects.
74.40.+k - Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.).

© EPLA 2009