We have investigated the pressure-induced phase transition in BeO using a first-principles pseudopotential method within the generalized gradient approximation. The results show that the enthalpy of BeO with wurtzite structure is lower than that with zinc blende structure at $87\mathrm{GPa}$ and the same to rocksalt structure at $105\mathrm{GPa}$. However, from the point of view of enthalpy barrier, the wurtzite-zinc-blende-rocksalt phase transition sequence will not happen up to $200\mathrm{GPa}$ but only the wurtzite-rocksalt transition. The phase transition mechanism can be viewed as an orthogonal strain deformation: two strain contractions in $\left[10\overline{1}0\right]$ and [0001] direction and a strain expansion in [0100] direction.

• Received 1 January 2006

DOI:https://doi.org/10.1103/PhysRevB.73.184104