A NEW KINETIC TERM IN THE PHENOMENOLOGY OF LAYERED SUPERCONDUCTORS

We show that the Lawrence-Doniach free energy for layered superconduct ors can be derived from an anisotropic Ginzburg-Landau free energy wit h a spatially dependent coefficient for the quadratic term. Our deriva tion indicates that new terms are present as well, including couplings of the gradients of the order parameters of neighboring layers. These terms tend to make the sign of the order parameters alternate from la yer to layer, and may cause a phase transition in the presence of magn etic fields normal to the layers.