Magnetic-fieldinduced singlet-triplet phase transition in quasione-dimensional organic superconductorsN. Belmechri1, G. Abramovici1, M. Héritier1, S. Haddad2 and S. Charfi-Kaddour2
1 Laboratoire de Physique des Solides, UMR 8502, CNRS Université Paris-Sud 11 - 91405 Orsay, France
2 Laboratoire de Physique de la Matière Condensée, Faculté des Sciences de Tunis - Tunisia
received 1 August 2007; accepted in final form 4 September 2007; published November 2007
published online 28 September 2007
We propose a theoretical model of quasione-dimensional superconductors, with attractive electron-electron interactions dominant in the singlet d-wave channel and sub-dominant in the p-wave channel. We discuss, in the mean-field approximation, the effect of a magnetic field applied perpendicularly to the direction of the lowest conductivity. The lowest free energy phase corresponds to a singlet d-wave symmetry in low fields, but to a triplet symmetry in high fields. A first-order singlet-triplet phase transition is expected at moderate applied fields of a few teslas. We propose to ascribe the recent critical field and NMR experimental data, observed in superconducting (TMTSF)2ClO4 to such an effect.
74.70.Kn - Organic superconductors.
74.25.Op - Mixed states, critical fields, and surface sheaths.
74.20.Rp - Pairing symmetries (other than s-wave).
© Europhysics Letters Association 2007