Program Highlights for year 2008
Surface plasmons - collective oscillations of free charges - on metal surfaces have resulted in demonstrations of enhanced optical transmission, collimation of light through a subwavelength aperture, negative permeability and refraction at visible wavelengths, and second-harmonic generation.
Organic photovoltaic devices (OPVs) hold promise for a variety of applications requiring alternative energy generation. Through a collaboration betweenÂ’ Northwestern University MRSEC IRG 4 and Wright Patterson Air Force Base, a new strategy for characterizing the electrical and optical performance of operating OPVs has recently been developed.
A partnership between the NU-MRSEC and the Art Institute of Chicago provides fertile ground for curriculum development. Lisa Backus, a high school chemistry teacher and participant in the Center's 2006Â’ Research Experience for Teachers (RET) program was inspired by her summer research project working on conservation science problems of Ancient Chinese jades and Winslow Homer watercolors.
One of the key hurdles to building a large quantum computer is maintaining the coherence of the many individual two-level quantum mechanical systems, or qubits. Atoms and ions in a vacuum or nuclear spins in solids and liquids can have long coherence, but it is not yet known how well those systems can be scaled to make a large computer.
The energy E of a bowling ball increases as the square of its velocity (or momentum p). This is also generally true for electrons in solids, which are accurately described by the Schràƒ’¶dinger equation (Fig. 1a). However, in a small set of materials - e.g. bismuth, antimony and graphene - E increases linearly with p (Fig. 1b).
In a normal material, electrons repel each other due to their charge. In the copper-oxide superconductors, however, an attractive force develops between electrons that pairs them up at temperatures up to 140 degrees above absolute zero. Understanding the reason for this pairing has remained an elusive goal in condensed matter physics research over the past two decades.
In a recent publication in Nature, we reported bulk metallic glass (BMG) matrix
composites exhibiting >10% tensile ductility and Fracture Toughness comparable to or
exceeding the toughest metals known . These high performance composites
demonstrate the potential of metallic glass as revolutionary structural metals. The BMG matrix