Two-dimensional island dynamics: Role of step energy anisotropy

Studies of surface dynamics, including the kinetics of two-dimensional (2D) island coarsening/decay, shape fluctuations, and shape evolution, enable determination of the rate-limiting mechanisms, corresponding surface mass transport parameters, and step energies. Most models describing these phenomena assume isotropic (circular) or near-isotropic island shapes and, hence, isotropic step energies. However, even simple elemental metal surfaces are anisotropic and more complex compound surfaces such as the low-index planes of TiN, GaAs, GaN, ZnO, Al2O3, ZrO2, are highly anisotropic. Here, we describe recent progress toward developing generalized theoretical and experimental approaches, applicable for analyses of 2D island coarsening/decay kinetics, coalescence kinetics, and determination of orientation-dependent step energies and step stiffnesses, on both isotropic and highly anisotropic surfaces.