THE STABILITY OF SATELLITE FACES ON MODULATED CRYSTALS

Sphere growth experiments have been performed on a series of distorted beta-K2SO4- type structures, all having a modulated crystal structure . An inventory of all satellite forms occurring was made. The stabilit ies of these forms were found to be clearly dependent on the length of the modulation wave vector. The results were compared with a connecte d net analysis and calculations on surface energies in a (1 + 1)-dimen sional modulated crystal model. A qualitatively good agreement between experiments and theory was found. The selection rules of the superspa ce group were shown to be relevant.