Non-uniform state in 2D superconductors

¹ Centre de Physique Théorique et de Modélisation, Université Bordeaux 1, CNRS-URA 1537 - 33174 Gradignan Cedex, France
² Centre de Recherches sur les Très Basses Températures, laboratoire associé à l'Université Joseph Fourier, CNRS - BP 166, 38042 Grenoble cedex 9, France

Received: 7 February 1996
Accepted: 29 July 1996

Abstract

We have investigated for the first time the complete temperature dependence of the upper critical field H_c2 in 2D layered superconductors taking both the orbital and Pauli limits into account. It is demonstrated that in 2D superconductors the formation of the non-uniform Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase gives rise to an unusual temperature dependence of H_c2: for fields exactly parallel to the layers, H_c2 has a linear temperature dependence as ; for any other field orientation, provided that the initial slope of the critical field at is large, we predict at low temperature the appearance of a multiquanta vortex state, revealed by the oscillatory temperature dependence of . Such a new effect could be observed in low-T_c quasi-2D layered superconductors.