Symposium on 'The Role of Ledgers in Phase Transformations'

摘要

Research workers in many countries and in many different research areas have gradually come to realize that ledges play a central role in the growth of crystals from the vapor, liquid and solid phases. However, the structure of ledges is not easy to study experimentally or to analyze theoretically. Similarly, the kinetics of ledgewise growth pose substantial problems to the experimentalist intent on their measurement and to the theoretician studies attempting to account for these data mathematically. Both experimental and theoretical studies during the three major types of phase transformation enumerated have tended to develop more or less independently of each other. The observation of ledges with TEM and field ion microscopy was discussed with emphasizing methods of distinguishing between ledges and dislocations. One speaker make clear the theoretical as well as the experimental problems involved in making this distinction by referring to certain linear defects displayed in his slides as thingies This issue has greatly worried us in our recent AFOSR-sponsored research, and it was somewhat of a relief to find that this concern is shared by the best of the experts in the field. However, it is now clear that special efforts must be expended upon making this very important distinction--particularly when the ledges are only a few atomic layers high. (JHD)