Elastic model for stress–tensor-induced martensitic transformation and lattice instability in silicon under large strains

Abstract

Recent molecular dynamics simulations for phase transformations (PTs) Si I ↔ Si II under multiaxial loading revealed that lattice instability criteria for Si I ↔ Si II PTs are linear in the stresses σi normal to the cubic faces; instability stress σ3 depends on σ2 = σ1 and is independent of shears; for some stresses σ2 = σ1, the instability stresses σ3 are the same for direct and reverse PTs; at critical stress σ2 = σ1, the first-order PTs are substituted with the second-order PT. We demonstrated that these features can be qualitatively reproduced using the simplest model with quadratic elastic energy in terms of Lagrangian strain. IMPACT STATEMENT Various nontrivial features of the martensitic transformation and lattice instability under complex loading in silicon are reproduced using the simplest model with quadratic elastic energy in terms of Lagrangian strain.