Growth of thin alumina films on a vicinal NiAl surface

Dramatic changes in the surface morphology have been observed during the oxidation of stepped NiAl(16, 14, 1) by LEED and STM. The initial sequence of identical (1 1 0) terraces is lifted in favor of large, triangular planes, whose mean size is determined by the mismatch-induced stress that accumulates in the thin alumina film. The asymmetry of the original step direction on NiAl(16, 14, 1) with respect to the orientation of the two alumina reflection domains favors the formation of one domain type, for which the stress relief via NiAl step edges is particularly efficient.