STRAIN RELAXATION INDUCED 1-DIMENSIONAL AND 0-DIMENSIONAL STRUCTURES - BI ON GE(001)

The growth of bismuth on Ge(001) has been studied using scanning tunne ling microscopy. Deposition of one-monolayer (ML) Bi at room temperatu re and subsequent annealing at 500 K results in the formation of a wel l-ordered (2 x n) vacancy line network oriented perpendicular to the d imer rows. Deposition of two-monolayer Bi under the same conditions re sults in the formation of square-shaped pits with depths up to 10 ML. The edges of these pits run along the two dimer row directions. Carefu l analysis of these pits reveal that they mainly consist of (111) and (113) facets. We argue that the morphological transition from the vaca ncy line network to the square shaped pits pattern is driven by a modi fication of the surface strain tenser. (C) 1997 Elsevier Science B.V.