Field-angle dependence of the quasiparticle scattering inside a vortex core in unconventional superconductors

TL;DR

This paper theoretically examines how quasiparticle scattering rates inside vortex cores in unconventional superconductors depend on magnetic field orientation, revealing potential methods to identify pairing symmetry through microwave measurements.

Contribution

It introduces a theoretical framework showing the field-angle dependence of quasiparticle scattering rates varies with pairing symmetry, especially distinguishing between s-wave and d-wave superconductors.

Findings

Scattering rate $ extGamma$ depends on magnetic field direction and pairing symmetry.

Sign change in pair potential affects the behavior of $ extGamma$.

Microwave surface impedance measurements can identify pairing symmetry phases.

Abstract

We theoretically investigate the quasiparticle scattering rate $\varGamma$ inside a vortex core in the existence of non-magnetic impurities distributed randomly in a superconductor. We show that the dependence of $\varGamma$ on the magnetic field direction is sensitive to the sign of the pair potential. The behavior of $\varGamma$ is quite different between an s-wave and a d-wave pair potential, where these are assumed to have the same amplitude anisotropy, but a sign change only for the d-wave one. It is suggested that measurements of the microwave surface impedance with changing applied-field directions would be used for the phase-sensitive identification of pairing symmetry.