Phys.org April 4, 2023 Materials with an extremely low thermal and high electrical conductivity that are easy to process, foldable, and nonflammable are required for sustainable applications, notably in energy converters, miniaturized electronics, and high-temperature fuel cells. Given the inherent correlation between high thermal and high electrical conductivity, innovative design concepts that decouple phonon and electron transport are necessary. Researchers in Germany achieved a unique combination of thermal conductivity and electrical conductivity in electrospun nonwovens comprising carbon as the matrix and silicon-based ceramics as nano-sized inclusions with a sea-island nanostructure. The carbon phase modulates electronic transport for high electrical conductivity, […]
Category Archives: Advanced materials
MIT physicists predict exotic new phenomena and give “recipe” for realizing them
MIT News March 17, 2023 van der Waals (vdW) heterostructures formed by 2D magnets and semiconductors have provided a fertile ground for fundamental science and spintronics. Through first-principles calculations researchers at MIT have found a proximity exchange splitting of 14 meV (equivalent to an effective Zeeman field of 120 T) in the vdW magnet-semiconductor heterostructure MoS 2/CrBr 3, leading to a 2D spin-polarized half-metal with carrier densities ranging up to 1013 cm−2. They explored the effect of large exchange coupling on the electronic band structure when the magnetic layer hosts chiral spin textures such as skyrmions. A flat Chern band […]
Scientists thread rows of metal atoms into nanofiber bundles
Phys.org March 6, 2023 A class of 3D atomic wires of transition metal chalcogenides (TMC) structures consisting of bundles of TMC nanofibers held together by metallic atoms in between the fibers, all forming a well-ordered lattice in its cross section are of particular interest. Depending on the choice of metal, the structure could even be made to become a superconductor. Researchers in Japan demonstrated versatile method to fabricate indium (In)-intercalated W6Te6 (In–W6Te6) bundles with a nanoscale thickness. Atomic-resolution electron microscopy revealed that In atoms were surrounded by three adjacent W6Te6 wires. First-principles calculations suggested that their wire-by-wire stacking can transform […]
New method creates material that could create the next generation of solar cells
Science Daily February 24, 2023 Halide perovskites show ubiquitous presences in growing fields at both fundamental and applied levels. Discovery, investigation, and application of innovative perovskites are heavily dependent on the synthetic methodology in terms of time-/yield-/effort-/energy- efficiency. Conventional wet chemistry method provides the easiness for growing thin film samples but represents as an inefficient way for bulk crystal synthesis. A team of researchers in the US (Pennsylvania State University, U.S. Army CCDCAMC) has developed a universal solid state-based route for synthesizing high-quality perovskites by means of simultaneously applying both electric and mechanical stress fields during the synthesis, i.e., the […]
Anti-dust tech paves way for self-cleaning surfaces
Phys.org February 22, 2023 Dust accumulation is detrimental to optical elements, electronic devices, and mechanical systems and is a significant problem in space missions and renewable energy deployment. A team of researchers in the US (UT Austin, industry) fabricated and demonstrated antidust nanostructured surfaces that can remove close to 98% of lunar particles solely via gravity. The structures are fabricated using a highly scalable nanocoining and nanoimprint process, where nanostructures with precise geometry and surface properties are patterned on polycarbonate substrates. The dust mitigation properties of the nanostructures were characterized using optical metrology, electron microscopy, and image processing algorithms to […]
Designing advanced ‘BTS’ materials for temperature and long-wave infrared sensing
Phys.org February 20, 2023 Replicating the molecular structure and functional motifs of biological compounds often provide clues to advance material designs and offers a blueprint for unprecedented functionalities. An international team of researchers (USA – Caltech, South Korea) has developed a flexible biomimetic thermal sensing (BTS) polymer that was designed to emulate the ion transport dynamics of a plant cell wall component, pectin. Using a simple yet versatile synthetic procedure, they engineered the physicochemical properties of the polymer by inserting elastic fragments in a block copolymer architecture, making it flexible and stretchable. The thermal response of the flexible polymer outperformed […]
New ice is like a snapshot of liquid water
Science Daily February 2, 2023 The new form of ice is amorphous. Unlike ordinary crystalline ice where the molecules arrange themselves in a regular pattern, in amorphous ice the molecules are in a disorganised form that resembles a liquid. Researchers in the UK created a new form of amorphous ice by grinding crystalline ice into small particles using metal balls in a steel jar. They created a novel amorphous form of ice which had a density similar to that of liquid water and whose state resembled water in solid form. They named the new ice medium-density amorphous ice (MDA). To […]
Solids that are also liquids: Elastic tensors of superionic material
Phys.org January 30, 2023 Superionics display both solid- and liquid-like characteristics: as solids, they respond elastically to shear stress; as liquids, they display fast-ion diffusion at normal conditions. They are technologically relevant for energy, electronics, and sensing applications. Characterizing and understanding their elastic properties are needed to address their feasibility as solid-state electrolytes in all-solid-state batteries. However, static approaches to elasticity assume well-defined reference positions around which atoms vibrate, in contrast with the quasi-liquid motion of the mobile ions in fast ionic conductors. Researchers in Switzerland have derived the elastic tensors of superionics from ensemble fluctuations in the isobaric-isothermal ensemble, exploiting extensive Car-Parrinello simulations. They applied this approach to […]
Lightning Strikes Create a Strange Form of Crystal Rarely Seen in Nature
Science Alert January 30, 2023 An international team of researchers (Italy, University of South Florida, Caltech, Princeton University) report the discovery of a dodecagonal quasicrystal Mn72.3Si15.6Cr9.7Al1.8Ni0.6—composed of a periodic stacking of atomic planes with quasiperiodic translational order and 12-fold symmetry along the two directions perpendicular to the planes. They found it in a fulgurite consisting predominantly of fused and melted sand along with traces of melted conductor metal from a nearby downed power line. According to the researcher fulgurite may have been created by a lightning strike that combined sand with material from downed power line or from electrical discharges from the downed power line alone. It reached temperatures of at least 1,710 °C as indicated by the […]
Discovery of a new form of carbon called long-range ordered porous carbon
Phys.org January 11, 2023 Carbon structures with covalent bonds connecting C60 molecules have been reported but until now there was no process to produce large enough quantities for detailed characterization and exploration necessary for potential applications. An international team of researchers (China, South Korea) has developed a gram-scale preparation method for long-range ordered porous carbon (LOPC), from C60 powder catalysed by α-Li3N at ambient pressure. LOPC consists of connected broken C60 cages that maintain long-range periodicity. At a lower temperature, shorter annealing time or by using less α-Li3N polymerized C60 crystal forms due to the electron transfer from α-Li3N to […]