New low-energy crystal structure for silicon

Abstract

A minimum-energy path in strain space has been determined which takes cubic silicon into itself. Energies are computed using the Stillinger-Weber model potential and first-principles total-energy calculations. The energy along this path has an additional minimum corresponding to a crystal structure with a body-centered-tetragonal lattice and fivefold-coordinated atoms. Lattice-dynamics, molecular-dynamics, and elastic-constant calculations show the structure is stable.