HIGH-PRESSURE INVESTIGATIONS ON AMORPHOUS SELENIUM

We report the diamond anvil cell (DAC) high pressure powder X-ray diff raction studies on amorphous selenium (a-Se) under truly hydrostatic p ressure condition up to 20 GPa. Amorphous selenium exhibits a sharp an d irreversible transition to a hexagonal structure at 10.6 +/- 0.1 GPa . It is also known that metallization occurs in a-Se around this press ure. Some plausible arguments are provided to suggest that the amorpho us to crystalline transition may be driven by metallization.