The Structure and Phase Transition for CsBr under Ultra-High Pressure

In situ energy dispersive X-ray diffraction measurements on CsBr under pressure up to 115 GPa have been performed by using pressure device－diamond anvil cell (DAC) with synchrotron source. It is determined that the structure of CsBr is changed from simple cubic phase to tetragonal phase at about 53 GPa marked by the splitting of its strongest diffraction line (110) into two parts: (011) and (110). The lattice parameter ratio c/a has been measured from p=0 to the maximum pressure (corresponds to V/V0 range of 1～0.463). No pressure-induced metallization transition has been observed at higher pressure up to 115 GPa.