Temperature Dependence of the Ag+Bg-Mode of Raman Shift for CaWO₄ Crystal

抄録

The first-order Raman frequency shifts of the A_g(2)+B_g(2) mode in a CaWO₄ crystal were measured in the temperature range of 77-- 771K. The frequency shift for this mode changes very slowly with increasing temperature. The temperature dependence of the frequency shift of the A_g(2)+B_g(2) mode was analyzed using the lattice dynamical perturbative treatment. We found that the quartic anharmonic term of the first-order perturbation, as well as the cubic term of the second-order one, and thermal expansion contribute to the temperature dependence of the frequency shift of the A_g(2)+B_g(2) mode in a CaWO₄ crystal.