The previously developed soft-mode theory of surface reconstruction was applied to the (111) surface of silicon. It was shown that the mutual interaction of surface dynamic effective charges could cause the ideal equilibrium configuration of the surface atoms to be unstable, thus leading to reconstruction. This instability was studied in detail using lattice-dynamical methods and it was found that dynamic effective charges on the order of 0.5e could lead to the 2 x 1 reconstruction observed experimentally. The directions in which the atoms displace due to the instability were shown and a new atomic configuration for the reconstructed surface was thereby predicted. The results were found to be nearly independent of the details of surface relaxation, of the distribution of the dynamic effective charges, and of the supposed weakening of the short-range forces in the surface region.

Dynamic Effective Charge and Surface Reconstruction on Si(111). S.E.Trullinger, S.L.Cunningham: Physical Review B, 1978, 18, 1898-915