Collective interaction-driven ratchet for transporting flux quanta - art. no. 177002

We propose and study a novel way to produce a dc transport of vortices when applying an ac electrical current to a sample. Specifically, we study supe rconductors with a graduated random pinning density, which transports inter acting vortices as a ratchet system. We show that a ratchet effect appears as a consequence of the long range interactions between the vortices. The p inned vortices create an asymmetric periodic flux density profile, which re sults in an asymmetric effective potential for the unpinned interstitial vo rtices. The latter exhibit a net longitudinal rectification under an applie d transverse ac electric current.