Pressure-Induced Phase Transition in Paratellurite (TeO2)

Abstract

We report a pressure-induced phase transition in paratellurite which occurs at 9.0 kbar at room temperature. The transition appears to be second order and is driven by the soft acoustic mode $\rho V^2=\frac{1}{2}(C_{11}-C_{12})$ propagating along . This is the only known phonondriven transition that can be induced with pressure, but not with temperature, for which the details of the transition mechanism have been definitely established. The phase transition was investigated using Brillouin-scattering, ultrasonic-velocity, and dielectricconstant measurements.