An oblique-incidence optical reflectivity difference and LEED study of rare-gas growth on a lattice-mismatched metal substrate

We studied the growth of Xe on Nb(l10) from 33 K to 100 K using a combination of low-energy electron diffraction and an in situ oblique-incidence optical reflectivity difference technique. We found that a hexagonal close-packed Xe film grows after a transition layer of three monoatomic layers thick is formed. The first two monolayers, influenced by both the interaction with the Nb substrate and the Xe-Xe interaction, lack long-range order. The third monolayer forms a bulk-like hexagonal close-packed structure. Subsequently a bulk-phase Xe(l11) film grows in step-flow mode from 54 K down to 40 K. At 40 K, we observed a brief crossover to a layer-by-layer mode. At 33 K the growth proceeds in a kinetically limited multilayer or a three-dimensional island mode.