Abrikosov vortex escape from a columnar defect as a topological electronic transition in vortex core
A. S. Mel'nikov, A. V. Samokhvalov
Institute for Physics of Microstructures RAS, 603950 Nizhny Novgorod, Russia
Abstract
We study microscopic scenario of vortex escape from a
columnar defect under the influence of a transport current. For
defect radii smaller than the superconducting coherence length the
depinning process is shown to be a consequence of two subsequent
topological electronic transitions in a trapped vortex core. The
first transition at a critical current jL is associated with
the opening of Fermi surface segments corresponding to the
creation of a vortex-antivortex pair bound to the defect. The
second transition at a certain current jd > jL is caused by
merging of different Fermi surface segments, which accompanies the
formation of a freely moving vortex.