van Hove singularities and vortex motion in superconductors - art. no. 024508

When vortices move in a type-II superconductor under the action of an elect ric current, they interact with the crystal lattice generating acoustic wav es. This results in a radiation-friction component to the vortex dissipatio n, which peaks at values of vortex velocity where there are phonons in the Brillouin zone of the crystal with matching phase and group velocities (the van Hove condition). Thus sharp peaks are expected in the current-voltage characteristic resulting from an enhancement of acoustic power generated by moving vortices.