The step-flow growth of Cu on vicinal Cu surfaces, Cu (1 1 17) and Cu (0 2
24), is investigated by variable-temperature scanning-tunneling microscopy.
These vicinal surfaces have identical terrace widths but their step orient
ation differs by 45 degrees. Upon growth, the surfaces develop a step-meand
ering instability, resulting in an in-plane patterning of the surfaces with
a temperature- and flux-dependent characteristic wavelength lambda (u). Th
e instability-induced structural patterns depend on the step orientation an
d are the manifestation of the Bales-Zangwill instability in both cases. Th
e selected characteristic wavelength is interpreted as the interplay of a d
estabilizing effect due to the presence of the Ehrlich-Schwobel barrier and
a stabilizing mechanism presumably due to "diffusion noise." As a result,
lambda (u) is proportional to the one-dimensional nucleation length l(n) al
ong a straight step, involving the diffusion barrier along both the (110) a
nd (100) step orientations on Cu(001).