Theoretical study of the structural phase transformation of BeO under pressure

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