A transition from chain- to island-type structure is observed in Ir adatom cluster nuclei on Ir(100). For five or fewer adatoms the stable configuration is a nucleus in the form of a linear chain, whereas for six or more adatoms a two-dimensional island configuration is stable. This unusual transformation indicates the presence of relatively long-range interactions between the Ir adatoms.
- Received 11 April 1988
- Published in the issue dated 1 August 1988
© 1988 The American Physical Society