Coherent thermoelectric effects in mesoscopic Andreev interferometers

¹ Physics Department, University of Arizona - 1118 E. 4th Street, Tucson, AZ 85721, USA
² Institut Laue-Langevin - 6 rue Jules Horowitz, BP 156, 38042 Grenoble, France, EU

^a pjacquod@physics.arizona.edu

Received: 22 May 2010
Accepted: 8 September 2010

Abstract

We investigate thermoelectric transport through quantum chaotic, ballistic mesoscopic Andreev interferometers. We show that the ratio of the thermal and the charge conductances exhibits large oscillations with the phase difference φ between the two superconducting contacts, and that the Wiedemann-Franz law holds only when φ = π. A rather large average thermopower emerges whenever there is an asymmetry in the dwell times to reach the superconducting contacts. When this is the case, the thermopower is odd in φ. In contrast, when the average times to reach either superconducting contact are the same, the average thermopower is zero, in agreement with earlier works on diffusive Andreev interferometers. We show however that mesoscopic effects (analogous to universal conductance fluctuations) lead to a sample-dependent thermopower which is systematically even in φ.