OBSERVATION OF A HIGH-PRESSURE CINNABAR PHASE IN CDTE

Angle-dispersive powder-diffraction techniques with an image-plate area detector and synchrotron radiation have been used to reexamine the high-pressure behavior of cadmium telluride. We find that the well-known structural phase transition at approximately 3.5 GPa from the zinc-blende to NaCl structure actually involves two closely spaced transitions-zinc blende to cinnabar, and cinnabar to NaCl. This is the example of the cinnabar structure outside the mercury chalcogenides. The Cd and Te atoms are site ordered, and the coordination of the structure is closer to fourfold than is found in HgS cinnabar.