Vortex structure and dynamics in kagome and triangular pinning potentials - art. no. 104505

We study the dynamics of thermally driven superconducting vortices in two t ypes of periodic pinning potentials: kagome and triangular. For the first, second, and third matching fields, we obtain the corresponding ground-state vortex configurations and their phase diagrams. We analyze the system prop erties by looking at the vortex trajectories and the structure factor, as w ell as the linear and angular diffusion. The temperature versus pinning for ce phase diagram is analyzed in detail for each matching field. When the te mperature is varied, we observe several stages of lattice pinning and melti ng. In most of the cases we find, for decreasing temperature, first a pinni ng of vortices and afterwards a freezing transition of the interstitial vor tices. The intermediate regime corresponds to interstitial vortices in a co nfined liquidlike state and pinned vortices. The kagome pinning potential s hows interesting behavior at low temperatures: there is a phase with rotati ng vortex triangles caged by kagome hexagons ("cooperative ring elementary excitations"), and there is geometric frustration for T-->0 with a nearly d egenerate ground state.