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Highlights

Mar 6, 2014
University of Pennsylvania

The Directed Dance of the Defects

Randall Kamien, Kate Stebe and Shu Yang (IRG1), University of Pennsylvania

  The term “defect” suggests something to be avoided.  However, our team has developed an extensive toolkit to control the locations, shapes, and detailed geometry of so-called topological defects in liquid crystals, the same sorts of materials used in the $100bn/year display industry.  Our goal is to harness these defects to use them as cues for further directed- and self-assembly, as lenses and optical elements, and as building blocks for hierarchical materials.
Jan 27, 2014
Cornell University

Atomic Break Dancing in the World’s Thinnest Glass

P. Y. Huang, S. Kurasch, J. S. Alden, A. Shekhawat, A. A. Alemi, P. L. McEuen, J. P. Sethna, U. Kaiser, D. A. Muller, Science 342, 224-227 (2013)

Electron microscopy reveals the fundamental steps of bending An international team of Cornell researchers and collaborators was recently entered into the Guinness Book of World Records for fabricating the world’s thinnest pane of glass — only two atoms thick!
Cavitation in Block Copolymer Modified Epoxy Revealed by In Situ Small-Angle X-Ray Scattering
Cavitation in Block Copolymer Modified Epoxy Revealed by In Situ Small-Angle X-Ray Scattering
Intramolecular Exciton Transport in Conjugated Polymers
Intramolecular Exciton Transport in Conjugated Polymers
Jan 22, 2014
University of Minnesota - Twin Cities

Intramolecular Exciton Transport in Conjugated Polymers

David Blank (IRG-2)

Using a series of acceptor-polymer-acceptor triads, IRG-2 investigators have measured intramolecular exciton diffusion in poly-3(hexylthiophene) (P3HT) for the first time.
Magnetic Charge Crystallization in Artificial Spin Ice
Magnetic Charge Crystallization in Artificial Spin Ice
Jan 22, 2014
University of Minnesota - Twin Cities

Magnetic Charge Crystallization in Artificial Spin Ice

Chris Leighton (IRG-3), in collaboration with the Univ. of Illinois, Penn State, and Los Alamos

“Artificial spin ice” is a term used for arrays of nanoscale magnetic islands on lattices that geometrically frustrate inter-island interactions. 
(Wheeler et al., Nat. Commun.,4, 2197, 2013)
(Wheeler et al., Nat. Commun.,4, 2197, 2013)
Jan 22, 2014
University of Minnesota - Twin Cities

Ligand-free Colloids and Surface Doping of Silicon Nanocrystals

Uwe Kortshagen 

Inks of inorganic nanocrystals hold great promise for printed electronics but the widely used organic surfactants (ligands) needed to stabilize these inks degrade the electrical quality of the printed films.
(a) The non-local resistance anomaly observed in Fe/Cu spin valves (red points), in which the polarization of the current decreases with decreasing temperature.  The effect does not occur in Fe/Al (blue)or in Fe/Cu devices with Al interlayers.  (b)  The effect is due to the formation of a screening cloud around local moments (the Kondo effect).  The effect saturates at low temperature, but the polarization of the current is reduced below its ideal value.
(a) The non-local resistance anomaly observed in Fe/Cu spin valves (red points), in which the polarization of the current decreases with decreasing temperature. The effect does not occur in Fe/Al (blue)or in Fe/Cu devices with Al interlayers. (b) The effect is due to the formation of a screening cloud around local moments (the Kondo effect). The effect saturates at low temperature, but the polarization of the current is reduced below its ideal value.
Jan 22, 2014
University of Minnesota - Twin Cities

Kondo Physics at Ferromagnet/Normal Metal Interfaces

P. A. Crowell and C. Leighton

The idealized picture of an interface between two elemental materials is simply an abrupt transition between planes containing two different types of atoms.
Jan 19, 2014
Northwestern University

Enhanced Refractive Index Sensing with Monodisperse Faceted Plasmonic Nanoparticles

Yu Jin Shin, Emilie Ringe, Michelle L. Personick, M. Fernanda Cardinal, Chad A. Mirkin, Laurence D. Marks, Richard P. Van Duyne, and Mark C. Hersam

The shape-dependent optical properties of metal nanostructures have motivated efforts to correlate nanoparticle structure with plasmonic behavior. In particular, gold bipyramids (BPs) are of interest due to their sharp tips that lead to strong localized field enhancement and high sensitivity to the surrounding environment. However, despite their potential, relatively few reports have studied the optical properties of sub-100 nm BPs due to their relatively low synthetic yields. To overcome this issue, density