Elastic softening and hardening at intersections between twin walls and surfaces in ferroelastic materials

Surfaces play a key role during ferroelastic switching and define the interactions of materials with ionic species biological systems. Here, we perform molecular dynamics simulations identify ridges valleys rounded singularities around intersections between twin walls surfaces. Two dominant length scales stem from elastic bending surface layer (>30 lattice units) local atomic reshuffles (some five units). For static walls, which do not shift laterally under external stress, intrinsic change in Young’s modulus involves softening near hardening ridges. The boundary-induced changes are order 0.7%.