Clean and well-annealed (103) surfaces were studied by means of scanning tunnelling microscopy and low-energy electron diffraction. They exhibited large 1 x 4 reconstructed (103) terraces, together with tent-like protrusions which consisted of (105), {216}, and {81 16} facets. On the basis of the scanning tunnelling microscopic images, atomistic models were proposed for the (103) 1 x 4, (216) 1 x 1, and (105) 1 x 2 surfaces. The 2 former surfaces consisted only of nano-scale (113) terraces and thus belonged to the (113) family, while the latter consisted only of nano-scale (001) terraces and thus belonged to the (001) family. The mini (001) terraces, of which the (105) 1 x 2 reconstruction consisted, formed a chequerboard pattern; thus implying that there was a stress-relaxation force driving the reconstruction. These surface structures demonstrated that Herring's faceting theorem could be valid down to atomic scales, provided that atomic-scale facets could be linked to form a large surface by low-energy edges and/or corners.

Z.Gai, R.G.Zhao, H.Ji, X.Li, W.S.Yang: Physical Review B, 1997, 56[19], 12308-15