title: Lattice dynamics of the Zn-Mg-Sc icosahedral quasicrystal and its Zn-Sc periodic 1/1 approximant.
abstract: Quasicrystals are long-range-ordered materials that lack translational invariance, so the study of their physical properties remains a challenging problem. Here, we have carried out inelastic-X-ray- and neutron-scattering experiments on single-grain samples of the Zn-Mg-Sc icosahedral quasicrystal and of the Zn-Sc periodic cubic 1/1 approximant, with the aim of studying the respective influence of the local order and of the long-range order (periodic or quasiperiodic) on lattice dynamics. Besides the overall similarities and the existence of a pseudo-gap in the transverse dispersion relation, marked differences are observed, the pseudo-gap being larger and better defined in the approximant than in the quasicrystal. This can be qualitatively explained using the concept of a pseudo-Brillouin-zone in the quasicrystal. These results are compared with simulations on atomic models and using oscillating pair potentials, and the simulations reproduce in detail the experimental results. This paves the way for a detailed understanding of the physics of quasicrystals.
authors.affiliation: Sciences et Ingénierie des Matériaux et Procédés, INPGrenoble CNRS UJF, BP 75 38402 St Martin d'Hères Cedex, France. Marc.de-boissieu@ltpcm.inpg.vr
authors.forename: Marc
authors.initials: M
authors.lastname: de Boissieu
authors.forename: Sonia
authors.initials: S
authors.lastname: Francoual
authors.forename: Marek
authors.initials: M
authors.lastname: Mihalkovic
authors.forename: Kaoru
authors.initials: K
authors.lastname: Shibata
authors.forename: Alfred Q R
authors.initials: AQ
authors.lastname: Baron
authors.forename: Yvan
authors.initials: Y
authors.lastname: Sidis
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishimasa
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wu
authors.forename: Thomas
authors.initials: T
authors.lastname: Lograsso
authors.forename: Louis-Pierre
authors.initials: LP
authors.lastname: Regnault
authors.forename: Franz
authors.initials: F
authors.lastname: Gähler
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsutsui
authors.forename: Bernard
authors.initials: B
authors.lastname: Hennion
authors.forename: Pierre
authors.initials: P
authors.lastname: Bastie
authors.forename: Taku J
authors.initials: TJ
authors.lastname: Sato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takakura
authors.forename: Roland
authors.initials: R
authors.lastname: Currat
authors.forename: An-Pang
authors.initials: AP
authors.lastname: Tsai