Bcc-fcc structure transition of Te

A group 16 element, tellurium (Te) undergoes numerous structural phase transitions under high pressure. Up to now, five different crystalline modifications have been identified at pressure up to 36 GPa: trigonal (Te-I at ambient pressure), monoclinic (Te-II at 4 GPa), incommensurate monoclinic (Te-III at 4.5 GPa), beta-Po type (Te-IV at 23 GPa and 473 K) and bcc (Te-V at 29 GPa). The pressure-induced successive structural phase transitions are accompanied by an increase in the coordination number of Te atoms: 2-4-6-8. Therefore, a transition to the structure with larger coordination number such as fcc or hcp is expected with further compression. In this paper, in order to explore the post-bcc phase, the synchrotron radiation x-ray powder diffraction experiments of Te at pressure up to 255 GPa and at room temperature have been carried out and the bcc-fcc structure transition is reported.