ATOMIC STRING POTENTIALS AND THE FORM OF [0001] ZONE-AXIS PATTERNS OFGAS, GASE AND INSE

The relationship between the form of hexagonal zone axis patterns and the projected atomic potential is explored as a method for polytype id entification of GaS, GaSe and InSe. As the various known polytypes of these materials project to give unit cells with very different simple- string potentials this relationship may be exploited by making use of previous related work. It is found that this method is simple to apply and consistent with the results of more conventional analyses based o n the symmetry of convergent beam electron diffraction patterns. Growt h faults could, however, cause ambiguities in the method of analysis.