AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP35
Structure Transformation of Palladium and Iridium Clusters on the W (110) Surfaces at Initial Stage

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: T.-Y. Fu, National Taiwan Normal University, Taiwan, ROC
Authors: T.-Y. Fu, National Taiwan Normal University, Taiwan, ROC
Y.-H. Wang, National Taiwan Normal University, Taiwan, Taiwan R.O.C.
T.T. Tsong, Institute of Physics, Taiwan
Correspondent: Click to Email
The initial stages of cluster nucleation of Pd or Ir adatoms on W (110) surfaces and in the vicinity of surface steps are observed directly by a field ion microscope (FIM). At the beginning, the most stable structures of Pd and Ir clusters are both linear chains, which are parallel to the nearest-neighbor stacking directions of the substrate. Different to the Pd clusters which the preferred structure is a 2-D compact island when the chain length is beyond 8 atoms, the linear Ir chains are apparently more stable and the greater coverage and higher temperature are necessary conditions for 1-D to 2-D transition. Both of Pd and Ir 2-D islands are pseudomorphic structure. As the number of Pd adatoms increasing to approximate monolayer coverage, the structures of clusters transfer to three-dimensional island. The structure transition from bcc (110) to fcc (111) of 3-D Pd clusters is shown. The quit complex transform behaviors of Ir clusters are also discussed.