An atomic-scale study of the Co induced dendrite formation on Pt(111)

We have studied the initial growth of Co on the Pt(111) surface in a temper ature range of 300-400 K with scanning tunneling microscopy, low energy ion scattering and Auger electron spectroscopy. In agreement with previous wor k by Grutter and Durig, when depositing 0.1 ML Co on Pt(111) at 400 K, the formation of large dendrites is observed. These dendrites are formed in con junction with a Co induced local reconstruction of the Pt(111) surface, res ulting in dislocations. The dendrites, however, show no evidence for any di slocations below their surface, the local reconstruction is observed to be lifted by the formation of the dendrites. LEIS data suggest that the dendri tes consist mainly of Pt, implying, together with the STM data, that Co is incorporated underneath the Pt. A model for this process is proposed. (C) 1 999 Elsevier Science B.V. All rights reserved.