Category: U.S. Department of Energy

  • A New Approach to Accelerate the Discovery of Quantum Materials

    (Funded by the U.S. Department of Energy, the National Science Foundation, and the National Aeronautics and Space Administration)
    For the first time, researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), Dartmouth College, Penn State, the University of California, Merced, and Université Catholique de Louvain in Belgium have demonstrated an approach that combines high-throughput computation and atomic-scale fabrication to engineer high-performance quantum defects. The researchers developed state-of-the-art, high-throughput computational methods to screen and accurately predict the properties of more than 750 defects in a two-dimensional material called tungsten disulfide. Then, working at the Molecular Foundry, a user facility at Berkeley Lab, the researchers developed and applied a technique that enables the creation of vacancies in tungsten disulfide and the insertion of cobalt atoms into these vacancies.

  • Surface oxygen functionality controls selective transport of metal ions through graphene oxide membranes

    (Funded by the U.S. Department of Energy)
    Scientists from the U.S. Department of Energy’s Pacific Northwest National Laboratory have discovered that reducing graphene oxide membranes with ultraviolet light alters the oxygen functional groups on the graphene oxide surface. This modification results in a novel separation mechanism that is selective for charge rather than size. Exposure to ultraviolet light selectively removed hydroxyl groups from the graphene oxide planes, leading to enhanced interactions of metal cations with functional groups located at the edges of the graphene oxide. This, in turn, resulted in a lower ratio of free mobile lithium cations in solution compared to calcium cations.

  • Nano-confinement may be key to improving hydrogen production

    (Funded by the U.S. Department of Energy)
    Researchers from the U.S. Department of Energy’s Lawrence Livermore National Laboratory, Columbia University, and the University of California, Irvine, have discovered a new mechanism that could boost the efficiency of hydrogen production through water splitting. This process relies on hydrated ion-permeable ultrathin coatings (such as porous oxide materials), which are used to select chemical species. Using advanced simulations, the scientists revealed that water confined within nanopores smaller than 0.5 nanometers shows significantly altered reactivity and proton transfer mechanisms. “This insight could pave the way for optimizing porous oxides to improve the efficiency of hydrogen production systems by tuning the porosity and surface chemistry of the oxides,” said Hyuna Kwon, one of the scientists involved in this study.

  • Atomically thin transducers could one day enable quantum computing at room temperature

    (Funded by the U.S. Department of Defense and the U.S. Department of Energy)
    To function, quantum computers need to be kept very cold – just a few degrees above absolute zero. Now, researchers at Northeastern University, the University of California, Berkeley, the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, and the National Institute for Materials Science in Tsukuba, Japan, have shown that one day, it might be possible to run quantum computers at room temperature. The researchers identified novel van der Waals heterostructures (created by combining layers of atomically thin materials, including graphene) that allow control of the coherent movements of atoms out of their equilibrium positions – also called acoustic phonons – at terahertz frequencies. With current quantum computer transistors, the control of acoustic phonons is limited to the gigahertz range. So, increasing the range of these transistors into terahertz frequencies – an increase by a factor of a thousand – opens the possibility of running quantum computers at room temperature.

  • SLAC’s high-speed electron camera uncovers new ‘light-twisting’ behavior in ultrathin material

    (Funded by the U.S. Department of Energy, U.S. Department of Defense, and the National Science Foundation)
    Researchers from the U.S. Department of Energy’s SLAC National Accelerator Laboratory and Argonne National Laboratory; Stanford University; Harvard University; Columbia University; Florida State University; and the University of California, Los Angeles, have discovered new behavior in an 50-nanometer-thick two-dimensional material, which offers a promising approach to manipulating light that will be useful for devices that detect, control or emit light, collectively known as optoelectronic devices. Optoelectronic devices are used in light-emitting diodes (LEDs), optical fibers, and medical imaging. The researchers found that when oriented in a specific direction and subjected to linearly polarized terahertz radiation, an ultrathin film of tungsten ditelluride circularly polarizes the incoming light.