Phonon lineshapes in the vortex state of the phonon-mediated superconductor YNi${}_2$B${}_2$C

Abstract

We present an inelastic neutron scattering study of phonon lineshapes in the vortex state of the type-II superconductor YNi${}_2$B${}_2$C. In a previous study [Phys. Rev. Lett. \textbf{101}, 237002 (2008)] it was shown that certain phonons exhibit a clear signature of the superconducting gap $2\Delta$ on entering the superconducting state. Our interest was to find out whether or not the lineshape of such phonons reflects the inhomogeneous nature of the vortex state induced by a magnetic field smaller than the upper critical field $B_{c2}$ .We found that this is indeed the case because the observed phonon lineshapes can be well described by a model considering the phonon as a local probe of the spatial variation of the superconducting gap. We found that even at $B=3\mathrm{T}$, where the inter-vortex distance is less than $300$Å, the phonon lineshape still shows evidence for a variation of the gap.

References in corpus (2)

• Direct observation of the superconducting gap in phonon spectra
• Superconductivity-Induced Distortions of Phonon Lineshapes in Niobium

Cited by in corpus (1)

• Superconducting energy gap of $2H$-NbSe${}_2$ in phonon spectroscopy