NONUNIFORM STATE IN 2D SUPERCONDUCTORS

We have investigated for the first time the complete temperature depen dence of the upper critical field H-c2 in 2D layered superconductors t aking both the orbital and Pauli limits into account. It is demonstrat ed that in 2D superconductors the formation of the non-uniform Fulde-F errell-Larkin-Ovchinnikov (FFLO) phase gives rise to an unusual temper ature dependence of H-c2: for fields exactly parallel to the layers, H -c2 has a linear temperature dependence as T --> 0; for any other fiel d orientation, provided that the initial slope of the critical field a t T = T-c is large, we predict at low temperature the appearance of a multiquanta vortex state, revealed by the oscillatory temperature depe ndence of H-c2. Such a new effect could be observed in low-T-c quasi-2 D layered superconductors.