Solid-Phase Silicon Homoepitaxy via Shear-Induced Amorphization and Recrystallization

We study mechanically induced phase transitions at tribological interfaces between silicon crystals using reactive molecular dynamics. The simulations reveal that the interplay between shear-driven amorphization and recrystallization results in an amorphous shear interface with constant thickness. Different shear elastic responses of the two anisotropic crystals can lead to the migration of the amorphous interface normal to the sliding plane, causing the crystal with lowest elastic energy density to grow at the expense of the other one. This triboepitaxial growth can be achieved by crystal misorientation or exploiting elastic finite-size effects, enabling the direct deposition of homoepitaxial silicon nanofilms by a crystalline tip rubbing against a substrate.