Raman spectroscopy of cubic boron nitride under extreme conditions of high pressure and temperature

摘要

Raman spectroscopy in the diamond cell has been used to determine the pressure dependence at high temperature of the transverse optical phonon (TO) of cubic boron nitride to 1750 K at a maximum pressure of 40 GPa, and up to 2300 K at 26 GPa. We have identified extrinsic (volume-dependent) and intrinsic contributions to the experimental frequency and find that the intrinsic contribution is only weakly pressure-dependent. These data establish a high-temperature pressure scale to at least 1700 K. Ab initio calculations to 80 GPa are in excellent agreement with the experiment at low temperatures.