SHAPE OSCILLATIONS IN GROWTH OF SMALL CRYSTALS

The equilibrium shape of a large crystal is uniquely determined by the anisotropic surface energy. In sharp contrast, we show here that the equilibrium shape of a small crystal is not unique, for temperatures below the roughening temperature. Instead, the degree of facetting is an oscillatory function of crystal size. Using low-energy electron microscopy, we observe oscillations in the shape of silver crystallites as they grow; we demonstrate theoretically that such oscillations with size occur even in thermodynamic equilibrium.