title: Lattice vibrations in an α- and β-AgCuS superionic conductor: experimental time-of-flight inelastic neutron scattering studies.
abstract: Inelastic neutron scattering (INS) measurements of a powder specimen of cation conducting AgCuS have been performed in its β-phase at 298 and 348 K and in its α-phase at 398 K by neutron time-of-flight (TOF) scattering. The neutron-weighted phonon density of states, G(ε), of the superionic and non-superionic phases of AgCuS has been obtained. G(ε) reveals a non-Debye behaviour at low energy that is caused by the presence of low-energy modes at 2.6 meV observed in the dynamic structure factor. The origin of this mode is not clear. The [Formula: see text] phase transition at 366 K is accompanied by considerable softening of several modes and simultaneous broadening of all peaks that result in a large increase of quasi-elastic intensity. Thermodynamic variables have been derived on the basis of G(ε).
authors.affiliation: State Scientific Center-Institute for Physics and Power Engineering, Bondarenko Square 1, Obninsk 249033, Russia. Insitute for Material Science, Darmstadt University of Technology, Petersenstrasse 23, Darmstadt D-64287, Germany.
authors.forename: A N
authors.initials: AN
authors.lastname: Skomorokhov
authors.forename: D M
authors.initials: DM
authors.lastname: Trots
authors.forename: S G
authors.initials: SG
authors.lastname: Ovchinnikov
authors.forename: H
authors.initials: H
authors.lastname: Fuess