Phase transitions in tellurium at high pressure and temperature

Abstract

The structural phase transitions in tellurium have been studied up to $21\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ and $743\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ using powder-diffraction techniques. We find the incommensurate Te-III phase to be stable up to at least $743\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, and have determined the $P\text{\ensuremath{-}}T$ dependence of the incommensurate wave vector $q$. We also find that the rhombohedral $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Po}$ phase of Te, Te-IV, previously reported to exist at room temperature, is stable only above $315\phantom{\rule{0.3em}{0ex}}\mathrm{K}$.