Rotational epitaxy of a 'soft' metal overlayer on Si(111)

The observation of rotational epitaxy of an incommensurate 'soft' T1 metal overlayer on a pseudomorphic Si(111)1 x 1-T1 surface by STM is reported. Th e structural 'softness' of this two-dimensional overlayer is destroyed by a dditional metal atom deposition, which induces condensation into three-dime nsional island structures as a result of the quenching of a strain relaxati on mechanism. It is suggested that the 'soft' T1 metal adlayer represents a metastage in the three-dimensional island formation process of Stranski-Kr astanov growth. It is interesting that this metastable second T1 layer coll apses on further growth and becomes incorporated into the three-dimensional islands once these have nucleated. (C) 2000 Published by Elsevier Science B.V. All rights reserved.