STRUCTURES AND ENERGETICS OF PT, PD, AND NI ADATOM CLUSTERS ON THE PT(001) SURFACE - EMBEDDED-ATOM-METHOD CALCULATIONS

The structures and energetics of Pt, Pd, and Ni adatom clusters on the Pt(001) surface have been investigated using the embedded-atom method (EAM). The stable configurations of Pt clusters are predicted to be linear chains oriented along the 110 directions for three and five adatoms and close-packed islands for four and six or more adatoms. These results are in agreement with a recent field-ion-microscopy (FIM) study and with previous EAM calculations [Schwoebel et al., Phys. Rev. B 40, 10 639 (1989)]. For Pd, the stable configurations are predicted to be close-packed islands except for three adatoms, for which a linear chain is the predicted stable configuration. Preliminary FIM observations, with Pd clusters containing up to six adatoms, agree with these predictions for four, five, and six adatoms, but are not conclusive concerning the stable configuration for three adatoms [G. L. Kellogg (private communication)]. For Ni, the stable configurations are predicted to be linear chains for all numbers of adatoms, and at this time no experimental observations have been reported. The similarities and differences in the results for Pt, Pd, and Ni adatoms are discussed, as well as the importance of substrate relaxations. © 1990 The American Physical Society.