ABSTRACT
Charles Reichhardt and Dr. Cynthia Olson, Los Alamos National
Laboratory
``Pattern formation in systems with competing interactions:
Applications to materials science''
A remarkable variety of patterns appear in two-dimensional systems when
there is a competition between long-range repulsion and short range
attraction. Recently, it was suggested that the patterns that form in
soft matter systems such as Langmuir monolayers, polymers, and gels
have analogs in electronic systems, such as in electron liquid crystals
where stripe like arrangements of charges can occur. Patterned states
appear in two-dimensional electron systems, high temperature
superconductors, and colossal magnetoresistive materials. Very little
is known about how thermal or quenched disorder affects these states,
what their transport properties are, or what is the minimal model
required to capture these phases. We simulate a simple model for
competing interactions which produces crystal, stripe, and bubble
phases. We find striking differences in the melting behavior of the
phases, ranging from filamentary melting of a stripe to correlated
dislocation formation in a crystal. Transport over quenched disorder
can restore order to each state, and produces experimentally measurable
signatures of the different phases.
Monday,
May 3, 2004
11:00 a.m. 432 Phy/Geo