G. Moras, L. Colombi Ciacchi,
C. Elsässer, P. Gumbsch, A. De Vita

Physical Review Letters, 105, (2010), 075502 1-4

We present a quantum-accurate multiscale study of how hydrogen-filled discoidal ?platelet? defects grow inside a silicon crystal. Dynamical simulations of a 10-nm-diameter platelet reveal that H2 molecules form at its internal surfaces, diffuse, and dissociate at its perimeter, where they both induce and stabilize the breaking up of highly stressed silicon bonds. A buildup of H2 internal pressure is neither needed for nor allowed by this stress-corrosion growth mechanism, at odds with previous models. Slow platelet growth up to micrometric sizes is predicted as a consequence, making atomically smooth crystal cleavage possible in implantation experiments.