Stability of the bcc Structure of Bismuth at High Pressure

Powder X-ray diffraction experiments were made for Bi up to the maximum pressure of 40 GPa. The high pressure bcc phase was found to be stable for a wide range of pressure above 7.7 GPa. Energy differences of the structure-dependent part of cohesive energy between the fcc, hcp, bcc and sc phases are calculated as a function of volume using the model pseudopotential method. It is shown that the bcc phase is stable relative to the other phases at high pressure in agreement with the experimental results.