Raman scattering study of alpha-quartz and Si(1-x)GexO2 solid solutions Auteur(s): Ranieri Vincent, Bourgogne David, Darracq S., Cambon Martine, Haines Julien, Cambon Olivier, Le Parc R., Levelut C., Largeteau Alain, Demazeau Gérard (Article) Publié: Physical Review B, vol. 79 p.224304 (2009) Ref HAL: hal-00434422_v1 DOI: 10.1103/PhysRevB.79.224304 WoS: 000267699300052 Exporter : BibTex | endNote 30 Citations Résumé: alpha-quartz-type Si1−xGexO2 solid solutions (x=0.06, 0.11, and 0.24) and pure SiO2 were investigated by Raman spectroscopy. Coupled and decoupled vibrational modes were identified at room temperature as a function of composition. Tetrahedral tilting librational modes involved in the displacive alpha<-->beta-quartz phase transition are decoupled. The wave number of the coupled A1 mode located at 464 cm−1 for pure alpha-quartz was found to vary quite linearly with germanium content. Raman spectra were recorded up to 1473 K. Substitution of germanium in the quartz lattice clearly improves the thermal stability of the alpha phase. The alpha<-->beta-quartz phase transition temperature increases from 846±1 K for x=0 to about 1300±50 K for x=0.24. At the same time, the dynamic disorder observed in quartz well below the transition is reduced in the solid solutions. |