Abstract:

Time-resolved in situ-applied scanning tunnelling microscopy (STM) has been used to study the homoepitaxial growth of Fe on Fe(ll0). Sequences of STM images taken during growth directly show the atomistics of the growth processes on the surface. These data are statistically analysed and compared with kinetic Monte Carlo simulations which include the correct symmetry of the bcc (110) surface. Two sets of activation barriers were used in the simulation. Applying simple bond-counting energetics the influence of the probabilities of different hopping events on the growth has been studied. Material-specific barriers calculated using a Finnis-Sinclair potential reproduce most of the real growth behaviour. A strongly anisotropic growth is found with islands elongated in [001] which is kinetically stabilized by a hindered diffusion at step edges along [001]. At room temperature, the presence of a step edge barrier prevents the interlayer mass transport nearly completely and leads to kinetic roughening and complete facetting of the surface.