Theoretical high-pressure studies of silicon VI

We have investigated Si theoretically under high compressions by means of first-principles self-consistent total-energy calculations within the local-density approximation using the full-potential linear-muffin-tin-orbital method. Our results confirm the recent high-pressure experimental observations of crystallographic phase transformations in Si [Hanfland et al., Phys. Rev. Lett. 82, 1197 (1999)]. The calculated transition pressure for the occurrence of the silicon-VI crystal structure agrees very well with the experimental data.