01. Imaging the elusive skyrmion: Neutron tomography reveals their shapes and dynamics in bulk materials 02. Light and sound waves reveal negative pressure 03. Material would allow users to ‘tune’ windows to block targeted wavelengths of light 04. Nanofluidic device generates power with saltwater 05. Novel approach towards nanomaterials developed 06. One-atom-thick ribbons could improve batteries, solar cells and sensors 07. Researchers advance topological superconductors for quantum computing 08. Researchers fabricate chip-based optical resonators with record low UV losses 09. Single sideband modulation technique can relax the bandwidth restriction 10. Transistor-inspired ultra-sensitive materials heat up advanced data security And others […]
Efficient fuel-molecule sieving using graphene
Phys.org September 22, 2023 Proton exchange membranes with high proton conductivity and low crossover of fuel molecules are required to realize advanced fuel-cell technology. The selective transportation of protons, which occurs by blocking the transportation of fuel molecules across a proton exchange membrane, is crucial to suppress crossover while maintaining a high proton conductivity. An international team of researchers (Japan, Germany) proposed a simple yet powerful method for optimizing the crossover-conductivity relationship by pasting sulfanilic-functionalized holey graphenes onto a Nafion membrane. Their results showed that the sulfanilic-functionalized holey graphenes supported by the membrane suppressed the crossover by 89% in methanol […]
Imaging the elusive skyrmion: Neutron tomography reveals their shapes and dynamics in bulk materials
Phys.org September 26, 2023 Commonly observed in thin systems as two-dimensional sheets, in three dimensions skyrmions form tubes that are thought to nucleate and annihilate along their depth on points of vanishing magnetization. However, a lack of techniques that can probe the bulk of the material has made it difficult to perform experimental visualizations of skyrmion lattices and their stabilization through defects. An international team of researchers ( Canada, USA – NIST, SUNY Buffalo, Germany) provided three-dimensional visualizations of a bulk Co8Zn8Mn4 skyrmion lattice through a tomographic algorithm applied to multiprojection small-angle neutron scattering measurements. Reconstructions of the sample showed […]
Light and sound waves reveal negative pressure
Phys.org September 25, 2023 Pressure is encountered in various fields – atmospheric pressure in meteorology, blood pressure in medicine, etc. Examining the physical properties of materials under a wide range of thermodynamic states is a challenging problem due to the extreme conditions the material must experience. Such temperature and pressure regimes, which result in a change in the refractive index and sound velocity, can be accessed by optoacoustic interactions such as Brillouin–Mandelstam scattering. An international team of researchers (Germany, France, Australia) demonstrated the Brillouin–Mandelstam measurements of nanolitre volumes of liquids in extreme thermodynamic regimes enabled by a fully sealed liquid-core […]
Material would allow users to ‘tune’ windows to block targeted wavelengths of light
Phys.org September 26, 2023 Dual-band electrochromism, the independent modulation of visible and near-infrared light by a single material, is highly desirable for smart windows to enhance the energy efficiency of buildings. Tungsten oxides are commercially important electrochromic materials, exhibiting reversible visible and near-infrared absorption when electrochemically reduced in an electrolyte containing small cations or protons. The presence of structural water in tungsten oxides has been associated with faster electrochromic switching speeds. A team of researchers in the US (North Carolina State University, UT Austin, Vanderbilt University) found that WO3·H2O, a crystalline hydrate, exhibited dual-band electrochromism unlike the anhydrous WO3. Making […]
Nanofluidic device generates power with saltwater
Nanowerk September 23, 2023 Researchers at the University of Illinois designed a nanofluidic device capable of converting ionic flow into usable electric power. Combining computational and analytical approach based on Green’s function technique and Boltzmann transport formalism they established the onset of electronic current in a doped silicon membrane induced by the long-range Coulomb interaction of ions flowing through a nanofluidic channel. Characterized by an open circuit voltage and short circuit current, the electronic Coulomb drag provided a new paradigm for power harvesting. Their model predicted a current amplification of the ionic drag current because of the large momentum transfer […]
Novel approach towards nanomaterials developed
Nanowerk September 25, 2023 In a typical approach for creating nanostructures ligands are grafted onto the surfaces of nanoparticles to improve the dispersion stability and control interparticle interactions. Ligands remain secondary and usually are not expected to order significantly during superstructure formation. Researchers in Germany investigated how ligands can play a more decisive role in the formation of anisotropic inorganic–organic hybrid materials. They grafted poly(2-iso-propyl-2-oxazoline) (PiPrOx) as a crystallizable shell onto SiO2 nanoparticles. By varying the PiPrOx grafting density, both solution stability and nanoparticle aggregation behavior could be controlled. Upon prolonged heating, anisotropic nanostructures formed in conjunction with the crystallization […]
One-atom-thick ribbons could improve batteries, solar cells and sensors
Science Daily September 21, 2023 Quasi-1D nanoribbons provide a unique route to diversifying the properties of their parent 2D nanomaterial, introducing lateral quantum confinement and an abundance of edge sites. Phosphorus-only materials do not conduct electricity very well, hindering their use for certain applications. Researchers in the UK created a new family of nanomaterials with the creation of arsenic–phosphorus alloy nanoribbons (AsPNRs). By ionically etching the layered crystal black arsenic–phosphorus using lithium electride followed by dissolution in amidic solvents, solutions of AsPNRs were formed. The ribbons were typically few-layered, several micrometers long with widths tens of nanometers across, and both […]
Researchers advance topological superconductors for quantum computing
Nanowerk September 21, 2023 The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. A team of researchers in the US (Oak Ridge National Laboratory, Rutgers State University of New Jersey) have shown superconductivity in monolayer (ML) FeTe1–ySey (Fe(Te,Se)) grown on Bi2Te3 by molecular beam epitaxy (MBE). Spin and angle-resolved photoemission spectroscopy (SARPES) directly resolved the interfacial […]
Researchers fabricate chip-based optical resonators with record low UV losses
Phys.org September 26, 2023 UV and visible photonics enable applications ranging from spectroscopic sensing to communication and quantum information processing. Photonics structures in these wavelength regimes tend to experience higher loss than their IR counterpart. Particularly in the near-UV band, on-chip optical microresonators have not yet achieved a quality factor beyond 1 million. A team of researchers in the US (Yale University, industry) developed ultra-low-loss photonic waveguides and resonators patterned from alumina thin films prepared by a highly scalable atomic layer deposition process. They demonstrated ultra-high Q factor of 1.5×106 at 390 nm, a record value at UV bands, and 1.9×106 […]