Lattice trapping and surface reconstruction for silicon cleavage on (111). Ab-initio quantum molecular dynamics calculations

This paper describes calculations by ab-initio quantum molecular dynamics methods of the dependence of lattice trapping energies on applied load for cracks running on (111) in silicon. A type of flexible boundary condition is used in which outer atom positions are relaxed using an empirical interatomic potential, while inner atoms are treated ab-initio. The form of the surface reconstruction which results from cleavage is also predicted for both the shuffle and glide cleavages. The fractional range of loads K_max/K_min in the lattice trapping range (without kinks is found to be 1.31 and the energy barrier to the advance of a straight crack line along [110] is found to be 0.24 eV per surface atom.