Saturation Density and Orientation of Discrete Nanostructures on the Surface of Ionic Crystals

The influence of substrate vacancies on the saturation density and orientation of islands upon vacuum condensation of metals onto ionic crystals is investigated for two specific systems. It is shown that the anomalous temperature dependence of the saturation island density in the high-temperature range can be associated with the mobility of vacancies and their trapping by the condensate-substrate interface. The nature of the discrimination of a 180° position of Au tetrahedral islands within each mirror plane of a CaF2 cleavage upon vacuum condensation in the temperature range of oriented crystallization (350–370°C) is revealed. It is demonstrated by the molecular dynamics method that the discrimination is caused by the predominant nucleation of Au clusters on anion vacancies of the CaF2 surface.