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When two identical particles are exchanged, the wave function is unchanged if they are bosons but changes sign if they are fermions. The fractional quantum Hall effect (FQHE) is due to particles that are “anyons,” where the wave function changes phase by arbitrary amounts. These cases were long considered Abelian (the order of exchange of multiple particles is irrelevant). Recently, however, a Sandia-led team obtained compelling evidence that some types of FQHE particles are non-Abelian. This profound result has important implications for quantum computing. (1100) ST&E, ER&N
Unexpected differences discovered between niobium and tantalum may lead to new electronic and photocatalytic materials as reported in an Oct. 28 Dalton Transactions cover article. Sandia researchers developed a “soft chemistry” route to niobium/tantalum oxide compounds. The alternative “volcano” method involves melting oxides at high temperatures. The “soft” method involves chemical finesse rather than brute force and offers new forms of these oxides including nanoparticles, coatings, and unprecedented compositions. Tantalum oxides are used in medical implants, hypoallergenic surgical tools, cell phone capacitors, and ceramics for encapsulating nuclear waste. (6300) ER&N, ST&E
Nanomaterials such as carbon nanotubes and semiconductor nanowires may possess unusual but useful properties in response to microwave radiation. Sandia researchers, collaborating with Penn State, made the first measurements of the fundamental high-frequency electrical conductance in arrays of carbon nanotubes and silicon nanowires across the same microwave spectrum used in telecommunications and radar. They showed that the nanomaterials’ frequency-dependent conductance behaves very differently from conventional macroscopic materials. This work was supported by a Nanometer-to-Micrometer LDRD-funded project and by the Readiness in Technical Base and Facilities program. (1100, 1800) ST&E
A Sandia team has carried out multimillion atom simulations of the shear rheology of nanoparticle suspensions to predict how the chemical interactions that occur among nanoparticles affect the behavior of nanoparticulate fluids during manufacturing. The team improved by more than 100 times the speed of the molecular dynamics code LAMMPS for nanoparticles in an explicit solvent. This work was supported by the National Institute for Nano Engineering (NINE) and by a cooperative research and development agreement with a five-company consortium to develop production-level computations for nanoparticle flow processing. (1100, 1400, 1500) ST&E
Sandia and University of Wisconsin researchers demonstrated that the sensitivity of carbon nanotubes to light is increased dramatically when they are coated with dye molecules. When exposed to light, these molecules change shape and induce a change in the electrical conductance of the nanotube. This discovery may allow for multicolor detection of low-intensity light at nanometer dimensions. It was highlighted in Nature in an article titled “Nanotubes see the light.” (8700) ST&E
A new simple self-assembly coating process was developed to functionalize nanoparticles and organize them into ordered arrays. The resulting films exhibit unusual functionality not previously observed in conventional processes, needed for anti-reflection coatings on sensor windows for military aircraft and unmanned aerial vehicles. This innovative self-assembly process offers significant advantages including reduced costs, increased manufacturing flexibility, improved logistics, and a tailored material response. This technical innovation, made possible through a Sandia/Lockheed Martin partnership, was recognized with a 2007 R&D 100 Award. (1800, 0330) ST&E