title: The temperature dependence of the phononic band gap of NaI.
abstract: The position and size of the energy gap in the phonon density of states of NaI single crystal have been investigated by inelastic neutron scattering in a wide range of temperatures from 10 to 700 K. The results reveal a pronounced temperature effect which effectively leads to closure of the phonon gap at temperatures in the range of 700-800 K. The results are discussed in the context of studies of possible intrinsic localized modes in the phonon gap of alkali halides.
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic. kempa@fzu.cz
authors.forename: M
authors.initials: M
authors.lastname: Kempa
authors.forename: P
authors.initials: P
authors.lastname: Ondrejkovic
authors.forename: P
authors.initials: P
authors.lastname: Bourges
authors.forename: J
authors.initials: J
authors.lastname: Ollivier
authors.forename: S
authors.initials: S
authors.lastname: Rols
authors.forename: J
authors.initials: J
authors.lastname: Kulda
authors.forename: S
authors.initials: S
authors.lastname: Margueron
authors.forename: J
authors.initials: J
authors.lastname: Hlinka