August 26, 2014When is an electron hole like a quasiparticle? More specifically, what happens when a single electron hole is doped into a two-dimensional quantum antiferromagnet? Quasiparticle phenomena in such a system are predicted by theory, but have eluded observation, complicating the understanding of electron behavior in high-temperature superconducting cuprates. Experimenters working at the U.S. Department of Energy′s Advanced Photon Source have cast new light on this classic problem in condensed matter physics and opened a new pathway for the study of high-temperature superconductors.
August 14, 2014One of the most common types of bacterial infection might soon give doctors and nurses fewer sleepless nights, thanks to a discovery made by scientists utilizing the U.S. Department of Energy′s Advanced Photon Source at Argonne National Laboratory.
August 13, 2014Raloxifene, a treatment for decreasing fracture risk in osteoporosis, works only partially by suppressing bone loss. Studies at the U.S. Department of Energy′s Advanced Photon Source revealed an additional mechanism underlying raloxifene action, providing an explanation for how this drug can achieve equivalent clinical benefit. These data, together with complementary techniques, help define a novel mechanism by which raloxifene increases inherent bone toughness.
August 5, 2014Measurements carried out at the U.S. Department of Energy′s Advanced Photon Source, coupled with state-of-the-art density functional theory simulations reveal that strong acids, such as hydrochloric acid, form counter-ion pairs in solution across all concentration, a result that had not been seen in gas-phase studies. The discovery suggests that it is not simply the release of protons — hydrogen ions — that is important for the properties of acids.
July 10, 2014Perovskites entice materials scientists with their ferroelectricity, ferromagnetism, catalytic activity, and oxygen-ion conductivity. Perovskites could be vastly improved by assembling them into thin films, but no one understood why thin films beat out bulk materials. Researchers working the U.S. Department of Energy′s Advanced Photon Source at Argonne National Laboratory used a groundbreaking approach to tease apart the thin-film structure and chemistry layer by layer and found that, instead of having a uniform distribution of elements, there were drastic differences in composition between the thin-film layers, an observation may help researchers design thin-film perovskites with enhanced activity and stability.
July 9, 2014Scientists using the U.S. Department of Energy′s Advanced Photon Source have demonstrated a conceptually new ultra-high-resolution inelastic x-ray scattering spectrometer able to provide valuable insight into how a material transforms from liquid to glass, one of the great mysteries of condensed matter physics. Understanding this process could shed new light on condensed matter theory and have practical applications such as the design of new drugs.
July 7, 2014Researchers working at the U.S. Department of Energy′s Advanced Photon Source at Argonne National Laboratory applied intense pressure to a compound of gadolinium and silicon, collecting information about a material well-suited to computer memory and magnetic sensors, and opening a new window into the complex lives of electrons under stress.
May 27, 2014Multiferroics are materials that exhibit a ferroelectric and magnetic order simultaneously. These orders have been the building blocks for technologically and economically important applications such as ferroelectric memory and spintronics, and present opportunities for efficient electric-field control of magnetism on ultrafast time scales. New research at the Universität Potsdam and at the U.S. Department of Energy Office of Science′s Advanced Photon Source is providing a better understanding of how these new properties come about and how best to harness them.
May 7, 2014Peptide amphiphiles are an emerging class of molecules that can be designed for novel therapies in advanced medicine. Researchers using high-brightness x-rays from the U.S. Department of Energy Office of Science′s Advanced Photon Source evaluated forces within the biological assemblies that can lead to cell breakdown and death, or to cell survival. These findings will be important in guiding future work to design biological materials for varied therapeutic use.
April 23, 2014Monochromatic x-ray topographic image for the (1 1 -2 4) reflection in grazing incidence showing a TED array along the <1 -1 0 0> direction . Three edge dislocations are schematically depicted in red. This image was obtained at beamline 1-BM of the APS.
April 9, 2014The demand for energy, especially cleaner energy, motivated work at the U.S. Department of Energy Office of Science′s Advanced Photon Source that characterized new porous metal-organic materials, which hold great promise for decreasing power-plant greenhouse gas emissions by removing carbon dioxide from post-combustion chamber gases.
April 1, 2014The dream of a hydrogen economy may depend on developing an energy-efficient strategy for splitting water into oxygen and hydrogen. The problem is that water bonds are very stable, requiring hefty energy inputs to break. Using measurements from the U.S. Department of Energy Office of Science′s Advanced Photon Source and Center for Nanoscale Materials, researchers analyzed the stability and composition of three small clusters of palladium that are under investigation as potential water-splitting catalysts and identified bonds that appear to be essential for catalytic function, allowing scientists to design better water-splitting catalysts.
March 27, 2014The atomic-scale structure and chemical properties of catalysts remain surprisingly mysterious, despite the critical roles that catalysts play in a variety of industrial and environmental applications. Researchers working at the U.S. Department of Energy Office of Science′s Advanced Photon Source teased out structural and chemical information about a single layer of vanadium oxide, a catalyst, supported on the surface of a titanium oxide crystal, making it possible for scientists to improve catalysts by strategically altering their structures.
March 18, 2014Dreaming up nanostructures that have desirable optical, electronic, or magnetic properties is one thing. Figuring out how to make them is another. Investigation by researchers at the U.S. Department of Energy′s Advanced Photon Source has revealed the precise form that the structures adopted, and points to ways of exercising still greater control over the final arrangement.
March 7, 2014Retroviruses like HIV-1, which causes AIDS, go to a lot of trouble to replicate themselves and further their infectious cycles. While the molecular details of this process are known, one mystery is how HIV-1 recognizes and fishes out its own RNA from among all the other RNAs in the nucleus, an essential step in viral replication. New research at the U.S. Department of Energy Office of Science′s Advanced Photon Source has defined the protein-structural basis for this process and may also help in the design of drugs that target HIV-1 infection for treatment of patients with AIDS.
February 26, 2014The key to understanding what causes changes in material conductivity lies in teasing out contributions from structural atomic arrangements and electron interactions. Researchers using high-energy x-rays from the U.S. Department of Energy Office of Science′s Advanced Photon Source disentangled these components in vanadium sesquioxide. By decoupling the effects of spin, charge, and lattice variables, they uncovered a mechanism that has eluded researchers for six decades.
February 24, 2014Light-emitting diodes use significantly less energy and have far longer lifetimes than do traditional incandescent bulbs. Scientists are using high-brightness x-rays from the U.S. Department of Energy Office of Science′s Advanced Photon Source to help explore and fine-tune new compounds in the form of nanoribbons that luminesce brightly in different colors and make more appealing white lights based on light-emitting diodes.
February 17, 2014Experiments at the U.S. Department of Energy Office of Science′s Advanced Photon Source studied the changes occurring in the domain pattern and atomic structure of a superlattice. These insights have the potential to extend the functionalities of complex oxides by providing the means to tune the field and time dependences of a material′s electronic properties, perhaps paving the way for their use in new, multifunctional microelectronic devices.
January 29, 2014When thin films of ferroelectric materials are grown on single-crystal substrates, they can develop domains with complex patterns. Changing the properties of the substrate and interfaces of the materials can control the size and shape of the domains and influence the material′s behavior, so to understand details of local polarization, it is important to accurately image the domains. At the U.S. Department of Energy Office of Science′s Advanced Photon Source, researchers utilized Bragg projection ptychography for ferroelectric domain imaging, potentially improving critical technologies such as memory storage.
January 27, 2014Toxic vehicle emissions, such as carbon monoxide and unburned hydrocarbons, are chemically converted to benign compounds by catalytic converters, which are valuable but expensive. To reduce costs, experiments are being done to lessen the amount of platinum and substitute palladium in the converters. Research at the U.S. Department of Energy Office of Science′s Advanced Photon Source indicates that a palladium/lanthanum-alumina catalyst may result in a reduced-cost catalytic converter with improved low-temperature carbon monoxide oxidation reactivity.
January 23, 2014Contrary to popular opinion, the iron found in the Earth's core is relatively weak. That is the finding from experiments carried out using x-rays from two U.S. Department of Energy Office of Science light sources including the Advanced Photon Source at Argonne National Laboratory show that. This weakness may explain how the crystal structure in the Earth's core has transformed over geological time scales.
January 22, 2014All organisms have mechanisms that they use to repair DNA damaged by ultraviolet light. New research shows that the current model for how UV repair functions must be reworked. Researchers from Harvard University utilizing the U.S. Department of Energy Office of Science’s Advanced Photon Source provide new insights into the fundamental mechanisms of DNA repair and into diseases that are caused by mutations in these genes.