The role of a simple surface defect, such as a step, for relaxing the stress applied to a semiconductor, was investigated by means of large-scale first-principles calculations. The results indicated that the step was the privileged site for initiating plasticity, with the formation and glide of 60° dislocations for both tensile and compressive deformations. The effect of surface and step termination upon the plastic mechanisms was also examined.Dislocation Formation from a Surface Step in Semiconductors - an ab initio Study. J.Godet, S.Brochard, L.Pizzagalli, P.Beauchamp, J.M.Soler: Physical Review B, 2006, 73[9], 092105 (4pp)