The effect of anisotropy on vortex lattice structure and flux flow in d-wave superconductors

We describe effects of anisotropy caused by the crystal lattice in d-wave superconductors using effective free energy approach in which only one order parameter, the d-wave order parameter field, is used. The Abrikosov parameter βA is calculated analytically for both static and moving vortex lattices. The analytic expression provides an unambiguous determination of the vortex lattice structure. We also calculate both direct and Hall I-V curves as functions of the angle between the current and the crystal lattice orientation. In particular, we show that near Hc2 the fourfold symmetry of the crystal lattice causes asymmetric motions of particles and holes, resulting in a non-vanishing Hall current.