date:Katholieke Univ Leuven, Vaste Stof Fys & Magnetisme Lab, B-3001 Louvain, Belgium; Chinese Acad Sci, Inst Phys, Natl Lab Supercondut, Beijing 100080, Peoples R China; Chinese Acad Sci, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China
Using numerical simulations we investigate the angular dependence of the vortex depinning transition at an incommensurate field above the first matching field in regular arrays of asymmetric pinning centers, modeled by the superposition of two interpenetrating square lattices of weak and strong pinning centers. The asymmetric pinning potentials can cause significant influence on the vortex motion when the vortices are driven at different angles with respect to the principle axes of the pinning lattice by the study of V-F-L curves. We propose that the anisotropic critical driving force for the vortex motion will be modulated by both the shape of the individual pinning center and the periodic structure of the pinning lattice. Moreover, we find that the anisotropic depinning transition of the driven vortices is very sensitive to the shift between the two pinning sublattices. (C) 2001 Elsevier Science B,V. All rights reserved.