Welcome!
We are investigating
topics in condensed matter physics that
span the range from hard to soft matter
research. A main theme is the study
of phenomena in systems far from equilibrium.
Much of what we work on has to do with
studying the interactions between many,
more or less identical "building
blocks" that make up larger, complex
structures and exhibit cooperative
effects. These building blocks in some
projects are macroscopic particles,
in other projects are colloids in the
10-100 micron range, or they can have
nanoscale dimensions, such as diblock
copolymer domains or metal nanocrystals.
We are particularly interested in studying
transitions that occur as a consequence
of cooperative interactions, such as
the jamming/unjamming transition from
static to moving configurations in granular
materials and colloids, the spontaneous
formation of order during nanoparticle
self-assembly far from equilibrium,
and the transitions between insulating,
metallic and superconducting phases.
The group uses a wide array of experimental
techniques, including magnetic resonance
imaging (in collaboration with the Department
of Radiology), x-ray tomography (at
Argonne's Advanced Photon Source) and
high-speed video for investigations
on granular materials, and optical or
electron-beam lithography, high-resolution
electron and scanning probe microscopies
as well as low-temperature (magneto-)
transport measurements for the study
of
nanoscale materials.
Our Current
Research Areas:
NEW: John Royer's
movie about granular
streams (1st
prize for video, Gallery of Nonlinear
Images, APS March Mtg 2009); see also
our letter just published in Nature
459 (6/25/09).
Fun links & press: Granular
jets on NPR's Science Friday,
Physics with a Bang! (pressure, gases, electricity) |
|
Image Gallery (for
info click on the images; more and
higher resolution images here)
|
metal-decorated diblock copolymer
thin films
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self-assembled array of gold nanoparticles,
each ~6nm in diameter
|
HRTEM of single Au nano rod (the
little black dots are individual gold
atoms)
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granular jet, produced by dropping
a steel sphere into fine loose sand
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granular convection
and size separation, imaged with MRI
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copolymer film near electrode prior
to E-field alignment
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MRI of jar filled with poppy seeds
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convection in vibrated granular material,
detected with spin-tagging MRI
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