title: Vibrational origin of the thermal stability in the highly distorted α-quartz-type material GeO2: an experimental and theoretical study.
abstract: We report an experimental and theoretical vibrational study of the high-performance piezoelectric GeO2 material. Polarized and variable-temperature Raman spectroscopic measurements on high-quality, water-free, flux-grown α-quartz GeO2 single crystals combined with state-of-the-art first-principles calculations allow the controversies on the mode symmetry assignment to be solved, the nature of the vibrations to be described in detail, and the origin of the high thermal stability of this material to be explained. The low-degree of dynamic disorder at high-temperature, which makes α-GeO2 one of the most promising piezoelectric materials for extreme temperature applications, is found to originate from the absence of a libration mode of the GeO4 tetrahedra.
authors.affiliation: Institut Charles Gerhardt Montpellier (ICGM), UMR 5253 CNRS-UM2-ENSCM-UM1, équipe C2M, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Guillaume.Fraysse@univ-lille1.fr
authors.forename: Guillaume
authors.initials: G
authors.lastname: Fraysse
authors.forename: Adrien
authors.initials: A
authors.lastname: Lignie
authors.forename: Patrick
authors.initials: P
authors.lastname: Hermet
authors.forename: Pascale
authors.initials: P
authors.lastname: Armand
authors.forename: David
authors.initials: D
authors.lastname: Bourgogne
authors.forename: Julien
authors.initials: J
authors.lastname: Haines
authors.forename: Bertrand
authors.initials: B
authors.lastname: Ménaert
authors.forename: Philippe
authors.initials: P
authors.lastname: Papet