Atomic mechanism of zinc-blende to NiAs high-pressure phase transition in BeTe

The atomic mechanism of the zinc-blende to NiAs structural transition under high pressure was investigated by crystallographic analysis and first-principles pseudopotential methods within the generalized gradient approximation. The relative sliding of less-close-packed cation layers {001}C along the <100> directions could be identified, accompanied by changes of lattice parameters and the fractional coordinates of anions, briefly referred to as the less-close-packed to most-close-packed cation layer transition mechanism. BeTe was taken as an example to study the changes of lattice parameters, enthalpy difference and the fractional coordinates of anions with the relative sliding of cations at equilibrium transition pressure. Furthermore, the change of the charge density along the transition path was investigated to characterize the formation of two new Be-Te bonds.