Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phonon Density-of-States in MgB2   We report inelastic neutron scattering measurements of the phonon
density-of-states in Mg11B2, which has a superconducting transition at 39.2 K.
The acoustic phonons extend in energy to 36 meV, and there are highly
dispersive optic branches peaking at 54, 78, 89 and 97 meV. A simple Born-von
Karman model is able to reproduce the mode energies, and provides an estimate
of the electron-phonon coupling of lambda~0.9. The estimated boron and
magnesium contributions to the isotope effect are in qualitative agreement with
experiment. The data confirm that a conventional phonon mechanism, with
moderately strong electron-phonon coupling, can explain the observed
superconductivity.

31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat