MIXED-SYMMETRY SUPERCONDUCTIVITY IN 2-DIMENSIONAL FERMI LIQUIDS

We consider a two-dimensional (2D) isotropic Fermi Liquid with attract ion in both s and d channels and examine the possibility of a supercon ducting state with mixed s and d symmetry of the gap function. We show that both in the weak-coupling limit and at strong coupling, a mixed s+id symmetry state is realized in a certain range of interaction. Pha se transitions between the mixed and the pure symmetry states are seco nd order. We also show that there is no stable mixed s+d symmetry stat e at any coupling.