Imma phase of germanium at ~80 GPa.

Abstract

Ge has been studied to 81 GPa with angle-dispersive diffraction techniques, using an image-plate area detector and high-brilliance synchrotron radiation from the European Synchrotron Radiation Facility. A previously unknown phase of Ge, with orthorhombic symmetry Imma, is found to exist above \ensuremath{\sim}75 GPa---between the well established $\ensuremath{\beta}$-tin and simple hexagonal phases. This phase is the same as that found recently between the $\ensuremath{\beta}$-tin and simple hexagonal phases of Si.