TILT MODULUS AND VORTICES IN LAYERED HIGH-TC SUPERCONDUCTORS

We investigate the properties of vortex-antivortex pairs and flux lines in layered superconductors. Interactions between vortices in different planes are weak and vortex pairs in a single layer dissociate at a Kosterlitz-Thouless transition. A flux line lattice (FLL) in a weak magnetic field H congruent-to H(c1) melts or evaporates at the same transition temperature. The tilt modulus of a FLL in a layered superconductor is considerably smaller than in a homogeneous superconductor and possibly is strongly influenced by Josephson tunneling.