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Nonequilibrium Interface and Surface Dynamics 2007
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Asymmetric transition states in quantum dots
CSIC Building (#406),
Seminar Room 4122.
Directions: home.cscamm.umd.edu/directions
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Asymmetric transition states in quantum dots
Professor
Brian Spencer
University of Buffalo
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Abstract:
We present a simple model for the shape transitions
of facetted quantum dots in strained solid films. In
the absence of substrate miscut, it is known that a
truncated pyramid minimizes the energy at small
volume while a dome minimizes the energy at larger
volume. Here we demonstrate the existence of an
asymmetric "half-dome" shape which acts as a
low-barrier metastable transition state in the
transition from the truncated pyramid to dome. Thus,
in a system with moderate fluctuations, half-dome
quantum dots should be observed, if only rarely. We
also consider the role of substrate miscut on the
energetics of quantum dot shape transitions. In the
presence of miscut, "half-pyramid" and "half-dome"
states play not only the role as intermediaries in
the transitions between truncated pyramid and dome,
but can even be stable equilibrium states.
This work is in collaboration with Jerry Tersoff. |
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