Electronic Structure of Vortices Pinned by Columnar Defects

Abstract

The electronic structure of a vortex line trapped by an insulating columnar defect in a type-II superconductor is analysed within the Bogolubov-de Gennes theory. For quasiparticle trajectories with small impact parameters defined with respect to the vortex axis the normal reflection of electrons and holes at the defect surface results in the formation of an additional subgap spectral branch. The increase in the impact parameter at this branch is accompanied by the decrease of the excitation energy. When the impact parameter exceeds the radius of the defect this branch transforms into the Caroli--de Gennes--Matricon one. As a result, the minigap in the quasiparticle spectrum increases with the increase in the defect radius. The scenario of the spectrum transformation is generalized for the case of arbitrary vorticity.

7 pages, 4 figures

References in corpus (4)

• Superconducting density of states and vortex cores of 2H-NbS2
• Electronic structure of multiquantum giant vortex states in mesoscopic superconducting disks
• Experimental determination of the number of flux lines trapped by micro-holes in superconducting samples
• Enhanced vortex heat conductance in mesoscopic superconductors

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