| Using both density-functional theory calculations and Monte Carlo simulations, we compute various key parameters that are used to model steps on vicinal surfaces.;In the first part, we discuss the importance of multi-site interactions (trios and quartos) in the lattice-gas characterization of adatom interactions. Using density-functional theory calculations, we show that multi-site interactions with substantial contributions from direct interactions are sensitive to adatom relaxations. Such sensitivity to adatom relaxations complicates the lattice-gas approach to modeling overlayer systems. Our results show that a careful consideration of relaxation effects is required to make connections with experiments.;In the second part, we use both density-functional theory calculations and kinetic Monte Carlo simulations to identify the impurity atom responsible for growth instabilities on Cu vicinals. In addition to that, we also show that a small quantity of codeposited impurities significantly alters the growth behavior. Our results indicate that growth morphologies could be controlled through the codeposition of an appropriate impurity. Hence, impurities could play a crucial role in nanostructuring of surfaces.;Step configurations have fruitfully been related to the worldlines of spinless fermions in one dimension. However, in addition to the realistic no-crossing condition, the fermion picture imposes a more restrictive non-touching condition, in the third part of this thesis, we use Metropolis Monte Carlo method to study the effects of loosening this non-touching condition on the resulting TWDs. Our results show that allowing step touching leads to an effective attraction in the step-step interaction strength measurements. We show that this effective attraction can be incorporated into the fermion picture as a finite-size effect. |
