Theoretical study of the structural phase transformation of BeO under pressure

We study the pressure induced phase transformation of BeO using a first-principles pseudopotential method within the local-density-functional approximation, and find a transition sequence from wurtzite to zinc blende, and then to rocksalt. With the generalized-gradient approximation for the exchange-correlation potential, we find the transition pressures to be increased significantly, without altering the transition sequence. The wurtzite structure transforms into the zinc-blende structure at 91 GPa, while the zinc-blende-to-rocksalt transition occurs at 147 GPa. This unusual transition sequence is attributed to the large charge asymmetry and the small bond length of BeO.