Phonon density-of-states in the new superconductor MgB2
Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
2 FLNP, Joint Institute for Nuclear Research, 141980 Dubna, Russia
Corresponding author: a firstname.lastname@example.org
Published online: 15 June 2001
We provide here experimental data on the phonon density-of-states of MgB2 obtained by the inelastic neutron scattering technique. The measurements were performed for the natural boron-based magnesium diboride with use of a time-of-flight neutron spectrometer. Several phonon bands were observed in the phonon spectrum at energies of about 33, 55, 82 and 99 meV. We show that the cut-off energy of the density-of-states occurs at around 105 meV which is much higher than expected so far from heat-capacity data and partially explains the high Tc value observed for MgB2. The characteristic phonon energies are indicative of an intermediate coupling regime in this compound. We conclude that a much needed neutron experiment aimed at the study of the isotopic effect in the phonon density-of-states of MgB2 is conceivable.
PACS: 74.70.-b – Superconducting materials (excluding high-Tc compounds) / 74.25.Kc – Phonons / 78.70.Nx – Neutron inelastic scattering
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001