Raman scattering in Ti 2 O 3 - V 2 O 3 alloys

摘要: Raman scattering of single crystals ${({\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{V}}_{x})}_{2}{\mathrm{O}}_{3}$ with $0\ensuremath{\le}x\ensuremath{\le}0.3$ has been measured between 80 and 700 \ifmmode^\circ\else\textdegree\fi{}K. All seven Raman-active phonons the ${D}_{3d}^{6}$ space-group symmetry were found to show appreciable changes in frequency, linewidth, relative intensity as a function temperature alloy composition vicinity semiconductor-to-metal transition. In particular, marked anomaly was observed behavior lowest frequency mode ${A}_{1g}$ symmetry. For $x\ensuremath{\lesssim}0.04$ it shows an initial softening followed by partial recovery going through transition temperature. Chi Sladek have similar decrease for sound velocity ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$. A qualitative discussion some these results is given terms free-energy band-crossing model Zeiger co-workers.