Europhys. Lett.
Volume 66, Number 4, May 2004
Page(s) 579 - 584
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 May 2004
Europhys. Lett., 66 (4) , pp. 579-584 (2004)
DOI: 10.1209/epl/i2004-10017-9

Phase coherence and the Nernst effect at magic angles in organic conductors

N. P. Ong, Weida Wu, P. M. Chaikin and P. W. Anderson

Department of Physics, Princeton University - Princeton, NJ 08544, USA

(Received 1 March 2004; accepted 17 March 2004)

A giant Nernst signal was recently observed for fields near crystallographic directions in $\chem{(TMTSF)_2PF_6}$. Such large Nernst signals are most naturally associated with the motion of pancake vortices. We propose a model in which phase coherence is destroyed throughout the sample except in planes closely aligned with the applied field H. A small tilt above or below the plane changes the direction and density of the penetrating vortices and leads to a Nernst signal that varies with the tilt angle of H as observed. The resistance notches at magic angles are understood in terms of flux-flow dissipation from field-induced vortices.

74.20.-z - Theories and models of superconducting state.
74.70.Kn - Organic superconductors.
72.15.Jf - Thermoelectric and thermomagnetic effects.

© EDP Sciences 2004