Eur. Phys. J. B 21, 465-467 (2001)
https://doi.org/10.1007/s100510170152

Phonon density-of-states in the new superconductor MgB₂

¹ 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 albert.furrer@psi.ch

Received: 19 March 2001
Published online: 15 June 2001

Abstract

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 T_c 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.