Field-induced gapless electron pocket in the superconducting vortex phase of YNi2B2C as probed by magnetoacoustic quantum oscillations

Abstract

By use of ultrasound studies we resolved magneto-acoustic quantum oscillation deep into the mixed state of the multiband nonmagnetic superconductor YNi2B2C. Below the upper critical field, only a very weak additional damping appears that can be well explained by the field inhomogeneity caused by the flux-line lattice in the mixed state. This is clear evidence for no or a vanishingly small gap for one of the bands, namely, the spheroidal alpha band. This contrasts de Haas--van Alphen data obtained by use of torque magnetometry for the same sample, with a rapidly vanishing oscillation signal in the mixed state. This points to a strongly distorted flux-line lattice in the latter case that, in general, can hamper a reliable extraction of gap parameters by use of such techniques.

6 pages, 6 figures

References in corpus (4)

• Magnetic field dependence of superconducting energy gaps in YNi2B2C: Evidence of multiband superconductivity
• Gapless Fermi Surfaces in Superconducting CeCoIn5?
• Gapless Fermi Surfaces in anisotropic multiband superconductors in magnetic field
• Magnetic field-induced gapless state in multiband superconductors