Crs. Da Silva et al., Theoretical investigation of the pressure induced cubic-diamond-beta-tin phase transition in the Si0.5Ge0.5, SOL ST COMM, 120(9-10), 2001, pp. 369-373
We theoretically studied the phase transition between the cubic-diamond and
beta -Sn structures for the Si0.5Ge0.5 alloy. We performed first principle
s calculations based on the density,functional theory, using the local-dens
ity approximation, and the variable cell shape molecular dynamics approach.
The alloy was modeled using an ordered zincblende type lattice, and we obt
ained a transition pressure of 8.35 GPa. We also calculated the enthalpy cu
rves at zero as well as at the transition pressure. At zero pressure, the e
nthalpy difference between the two phases is 0.016 Ry/atom, and there is a
barrier of approximately 0.026 Ry/atom. At the transition pressure, the ent
halpy barrier is still 0.018 Ry/atom, a sign of the strong first order char
acter of this phase transformation. (C) 2001 Published by Elsevier Science
Ltd.