The intensity of the quasi-elastic peak in He-atom time-of-flight spectra revealed that, at the 1050K phase transition, the Ge adatom concentration on the (111) surface increased from the 25% which was expected below the transition to about 31% above the transition. The wave-vector dependence of the energetic broadening of the same peak indicated that, above the transition temperature, the adatoms jumped to neighboring sites on a structurally well-defined substrate, with a liquid-like diffusion coefficient of 1.2 x 10-4 cm2/s. These results reconciled previously conflicting descriptions of the Ge high-temperature phase, and provided some initial information on the dynamic behavior of single adatoms on a semiconductor surface close to the melting point.

Behavior of single adatoms on the Ge(111) surface above the 1050K phase transition A.L.Glebov, J.P.Toennies, S.Vollmer: Physical Review Letters, 1999, 82[16], 3300-3