Dynamics of vortex shells in mesoscopic superconducting Corbino disks

摘要

In mesoscopic superconducting disks vortices form shell structures as recently observed in Nb disks. We study the dynamics of such vortices, driven by an external current I_0, in a Corbino setup. At very low I_0, the system exhibits rigid-body rotation while at some critical current I_(c,i) vortex shells rotate separately with angular velocities ω_i. This critical current I_(c,i) has a remarkable nonmonotonous dependence on the applied magnetic field which is due to a dynamically induced structural transition with a rearrangement of vortices over the shells similar to the Coster-Kronig transition in hollow atoms. Thermally activated externally driven flux motion in a disk with pinning centers explains experimentally observed ω_i as a function of I_0 and T and the dynamically induced melting transition.