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

Paper SS-TuP13
Stacking Fault Formation on Ir(111)

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

Session: Poster Session
Presenter: C. Busse, RWTH Aachen, Germany
Authors: C. Busse, RWTH Aachen, Germany
C. Polop, RWTH Aachen, Germany
T. Michely, RWTH Aachen, Germany
Correspondent: Click to Email
The formation of stacking faults during homoepitaxial growth was observed in the model system Ir/Ir(111) (crystal structure: face-centered cubic) under a wide range of deposition parameters (sample temperature and deposition rate) using scanning tunneling microscopy (STM). A quantitative model can explain the observations and proves that stacking faults form out of small clusters that can occupy faulted hexagonal close-packed adsorption sites with significant probability in thermal equilibrium. Metastable areas in the wrong stacking sequence then grow out of these clusters by sufficiently fast addition of adatoms. This model is expected to hold for other systems as well. Upon further growth, islands in the same stacking coalesce, but islands in different stacking sequences do not. In the latter case, atoms can, however, move to the energetically favourable, regular stacking via a kink-flip process (self-healing). In the ideal case this leads to a complete disappearance of the wrong stacking and a defect-free film evolves. This effect can be observed in situ by annealing experiments.