ENERGETICS OF LARGE LATTICE STRAINS - APPLICATION TO SILICON

We discuss the mathematical formalism of physically allowed lattice-in variant strains. When coupled with first-principles calculations of th e energy as a function of strain, this approach becomes a powerful too l for understanding large lattice strains in solids. We also present a n application of this tool to explore deformations of silicon, which p redicts, to our knowledge, a previously unknown metastable structure. The physical properties of this structure are described and a method f or obtaining it experimentally is explicitly provided.