Microscopic Theory of Vortex Pinning on Columnar Defects in Conventional and Chiral Superconductors

The mechanisms of individual vortex pinning and stability of multivortex configurations in different superconducting compounds and artificial structures are analyzed on the basis of microscopic theory, which allowed describing the corresponding modification of the anomalous spectral branches in the quasiparticle spectrum caused by the electron scattering at the defect. The individual pinning potentials and corresponding depinning currents are evaluated. The experimentally observable consequences for the scanning tunneling microscopy characteristics and high-frequency field response are discussed. The comparative study of the conventional and chiral superconductors allowed suggesting experimental tests probing the superconducting gap symmetry. The chiral superconductors are shown to reveal a strong dependence of the pinning characteristics on the mutual orientation of the magnetic field and internal angular momentum of the Cooper pair.