Inelastic neutron scattering studies of single crystal TmSe

Inelastic neutron scattering studies have been performed on a single crystal of stoichiometric (a = 5.71 A) TmSe. They confirm previous measurements performed on a polycrystalline sample which showed an inelastic line at 10 meV for T < approximately 40 K and another at 1 meV for T < Tsub(N) = 3.0 K. The energy of the 10 meV line exhibits weak dispersion across the Brillouin zone, while the intensity and linewidth show a stronger q dependence. The excitation is broader and less intense near the zone center than at the zone boundary. This feature results from the excitation of f-electrons across the hybridization gap formed when the localized f-electrons hybridize with the conduction band. The temperature and q dependences are consistent with a recent theoretical calculation of the neutron cross section for this case. (Auth.)