The structure of the clean (111) surface was studied, at temperatures of between 300 and 1882K, by means of X-ray scattering techniques. It was found that the structure was unreconstructed at homologous temperatures of less than 0.65, but reconstructed at higher temperatures to give a layer which was isotropically compressed and was incommensurate with the underlying bulk (111) planes. A disordered arrangement of discommensurations separated those regions with an ideal face-centered cubic stacking from regions with a faulted stacking. The compression of the surface layer, and the orientational order of the discommensurations, increased with increasing temperature.

A.R.Sandy, S.G.J.Mochrie, D.M.Zehner, G.Grübel, K.G.Huang, D.Gibbs: Physical Review Letters, 1992, 68[14], 2192-5