Sublimation of the (100)-(2 x 1) surface under a tensile strain, induced by dopant segregation, was investigated by means of low-energy electron microscopy. It was found that, at a given temperature, samples which contained relatively large concentrations of dopants exhibited a step-flow behavior during sublimation. On the other hand, the formation and proliferation of terrace vacancies, followed by disintegration of the surface steps, dominated the sublimation of lightly doped samples. Molecular dynamics simulations indicated that this marked difference in behavior was due to a strain-induced increase in the formation energy of dimer vacancies at the surface.

C.M.Roland M.G.Wensell, Y.Hong, I.S.T.Tsong: Physical Review Letters, 1997, 78[13], 2608-11