[Zurück]

A.S. El-Said, R.A. Wilhelm, R. Heller, S. Facsko, C. Lemell, G. Wachter, J. Burgdörfer, R. Ritter, F. Aumayr:
"Phase Diagram for Nanostructuring CaF₂ Surfaces by Slow Highly Charged Ions";
Physical Review Letters, 109 (2012), S. 1176021 - 1176025.

The impact of individual slow highly charged ions (HCI) on alkaline earth halide and alkali halide
surfaces creates nano-scale surface modifications. For different materials and impact energies a wide
variety of topographic alterations have been observed, ranging from regularly shaped pits to nanohillocks.
We present experimental evidence for the creation of thermodynamically stable defect
agglomerations initially hidden after irradiation but becoming visible as pits upon subsequent etching.
Awell defined threshold separating regions with and without etch-pit formation is found as a function of
potential and kinetic energies of the projectile. Combining this novel type of surface defects with the
previously identified hillock formation, a phase diagram for HCI induced surface restructuring emerges.
The simulation of the energy deposition by the HCI in the crystal provides insight into the early stages
of the dynamics of the surface modification and its dependence on the kinetic and potential energies.

http://dx.doi.org/10.1103/PhysRevLett.109.117602