Raman Scattering Study of the Alpha-Beta Phase Transition in Quartz

Abstract

The Raman spectrum of crystalline quartz has been studied at temperatures between -196 and 615°C. A weak mode of symmetry $A_1$ with room-temperature Raman shift of 147 ${\mathrm{cm}}^{-1\mathrm{}}$ is found to grow in intensity and move towards zero Raman shift as the alpha-beta transition is approached. This mode, rather than the 207-${\mathrm{cm}}^{-1\mathrm{}}$ mode, appears to play the fundamental role in the phase transition. The temperature dependence of the Raman shift of the new mode is given by ${\nu }^2\sim {|T-T_c|}^{\gamma }$ with $0.4<~\gamma <~0.5$.