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Nonequilibrium Interface and Surface Dynamics 2007
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Nanoscale Pattern Formation on Metal Surfaces
CSIC Building (#406),
Seminar Room 4122.
Directions: home.cscamm.umd.edu/directions
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Nanoscale Pattern Formation on Metal Surfaces
Professor
Norman Bartelt
Sandia National Laboratories
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Abstract:
Thin heteroepitaxial films on metals often are
observed to be arranged into complicated nanometer
scale patterns that can be very well ordered. In
this talk I will review several examples of our
efforts at Sandia Labs to quantitatively understand
the pattern formation process, revealing the (often
difficult-to-predict) delicate balance of the
competing mechanisms. Despite the similarity of
these patterns in different systems, a range of
different mechanisms can be responsible for their
formation. For example, sometimes the patterns are
the equilibrium state of the surface (Pb/Cu), other
times they are kinetic effects (Pd/Ru, Cr/W).
Although the thermodynamic driving force for pattern
formation is usually strain relief,
the mechanisms of strain relief can vary widely:
Sometimes bulk elastic relaxations are important (Pb/Cu,
Au/W), but often different, surface, relaxation
mechanisms play a role (O/Pt, S/Ag/Ru, CoAg/Ru). The
detail to which the pattern formation can be
understood in specific systems encourages the
attempt to control and use these patterns for
technological applications: I will show an example
of a system where knowledge of the atomistic
processes of pattern formation can be used to
control the position of large three dimensional
surface structures (Ag/W). |
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