Atomistic modeling comparison of Fe growth on Nb(1 1 0) and Nb growth on Fe(1 1 0)

The deposition of Fe on Nb(1 1 0), and the symmetric case, Nb on Fe(1 1 0), are studied by means of a simple modeling approach based on a quantum approximate technique, the BFS method for alloys. For Fe deposition on Nb, different regimes depending on the film thickness including layer-by-layer growth and formation of a surface alloy before stabilizing a pure Fe layer have been observed. Conversely, Nb growth on Fe is characterized by a specific temperature-dependent surface alloying pattern. A detailed atom-by-atom analysis using a single set of parameters reproduces all the experimentally known features based on a discussion of diffusion barriers, exchange mechanisms and the role of temperature via Monte Carlo simulations.