Phys.org October 10, 2022 Ultra-thin 2D materials are frequently grown by exposing a hot metal surface to a specific gas, which results in the gas decomposing on the metal and forming the desired 2D material. Due to the hot temperatures involved, it is difficult to monitor the growth of 2D materials during the several intermediate steps involved before the 2D material is completed. An international team of researchers (Austria, UK) utilized helium atom scattering to discover and control the growth of novel 2D h-BN nanoporous phases during the CVD process. They found that prior to the formation of h-BN from […]
Tag Archives: Advanced materials
Topological materials become switchable
Phys.org October 10, 2022 An international team of researchers (Austria, the Netherlands, USA – Los Alamos National Laboratory, Rice University) used a special material made of cerium, bismuth, and palladium to demonstrate that it is possible to control topological properties and even make them disappear completely at a certain point to achieve stable, robust properties that can be selectively turn on and off. This control was made possible by the internal structure of the excitations, which are responsible for charge transport: They carry not only electric charge, but also a magnetic moment—and this makes it possible to switch them through […]
Exotic electronic effect found in 2D topological material
Phys.org September 26, 2022 When external or intrinsic parameters break symmetries, global properties of topological materials change drastically. While a rich variety of non-trivial quantum phases could in principle also originate from broken time-reversal symmetry, realizing systems that combine magnetism with complex topological properties is remarkably elusive. An international team of researchers (Germany, USA – UC Davis) demonstrated that giant open Fermi arcs are created at the surface of ultrathin hybrid magnets where the Fermi-surface topology is substantially modified by hybridization with a heavy-metal substrate. The interplay between magnetism and topology allows for control of shape and the location of […]
Heat-resistant nanophotonic material could help turn heat into electricity
Nanowerk September 22, 2022 A team of researchers in the US (University of Michigan, University of Virginia) has developed materials using destructive interference phenomenon to reflect infrared energy while letting shorter wavelengths pass through. Using pulsed laser, they deposited oxides of calcium and titanium oxides. Oxides made the material more durable, less likely to degrade at high temperature, and they could be more precisely layered. The material controlled the flow of infrared radiation and was stable at temperatures of 2,000 degrees Fahrenheit in air, a nearly twofold improvement over existing approaches. After testing they confirmed that the material worked as […]
Lab grows macroscale, modular materials from bacteria
Nanowerk September 22, 2022 Engineered living materials (ELMs) embed living cells in a biopolymer matrix to create materials with tailored functions. While bottom-up assembly of macroscopic ELMs with a de novo matrix would offer the greatest control over material properties, the ability to genetically encode a protein matrix that leads to collective self-organization is lacking. A team of researchers in the US (Rice University, Lawrence Berkeley National Laboratory, UC Berkeley) grew ELMs from Caulobacter crescentus cells that display and secrete a self-interacting protein. This protein formed a de novo matrix and assembled cells into centimeter-scale ELMs. Discovery of design and […]
Biomimetic dual-color domes programmable for encryption
Nanowerk September 15, 2022 Spots with dual structural colors on the skin of some organisms in nature are of interest due to the unique function of their dye-free colors. However, imitation of them requires complicated manufacturing processes, expensive equipment, and multiple predesigned building blocks. Researchers in Hong Kong have developed a one-pot strategy based on the phase-separation-assisted nonuniform self-assembly of monosized silica nanoparticles to construct domes with dual structural colors. In drying poly(ethylene glycol)-dextran-based (PEG-DEX) droplets, monosized nanoparticles distributed nonuniformly in two compartments due to the droplet inner flow and different nanoparticle compatibility with the two phases. The dome colors […]
Modified microwave oven cooks up next-gen semiconductors
Nanowerk September 9, 2022 The doped semiconductor material must be sufficiently stable for the fabrication and operation of electronic devices. An international team of researchers (USA – Cornell University, industry, Taiwan, Spain) theorized that microwaves could be used to activate the excess dopants, but the previous microwave annealers produced “standing waves” that prevented consistent dopant activation. According to the researchers this discovery could be used to produce semiconductor materials and electronics appearing around the year 2025. It can potentially enable leading manufacturers to scale down to just 2 nanometers…read more. TECHNICAL ARTICLE
A new catalyst to slow down global warming
Phys.org September 2, 2022 An international team of researchers (Russia, USA – University of Notre Dame) has developed a new simplified method of producing industrial cobalt-nickel catalysts for carbon dioxide processing that makes the process simple and inexpensive. The catalysts are a bulk alloy with a porous surface and nanoscale grains that form foamy high-activity particles. Due to the structure and the synergistic interaction of Co with Ni, the catalysts are characterized by a more intense interaction with CO2 molecules and high stability. They focused on exploring the possibilities of full utilization of carbon dioxide, simplifying the production of effective […]
Researchers devise tunable conducting edge
Phys.org September 5, 2022 An international team of researchers (USA – UC Riverside, Israel, Japan) stacked monolayer WTe2 with an insulating ferromagnet of several atomic layer thickness—of Cr2Ge2Te6 (CGT) and found that the WTe2 had developed ferromagnetism with a conducting edge. The edge flow of the electrons was unidirectional and could be made to switch directions with the use of an external magnetic field. When only the edge conducts electricity, the size of the interior of the material is inconsequential, allowing electronic devices that use such materials to be made smaller. Currently, the technology works only at very low temperatures; […]
Damage-reporting and self-healing skin-like polymeric coatings
Nanowerk August 24, 2022 As it is difficult to determine whether the currently used polymeric coatings applied to the surfaces of automobiles, ships, etc. to protect them from the external environment are already damaged or not, these non-reusable coatings must be regularly replaced, leading to a large amount of waste generation and high disposal costs. Researchers in South Korea have demonstrated mechanochromic and thermally reprocessable thermosets that can be used for autonomic damage reporting and self-healing coatings. A mechanochromic molecule, spiropyran (SP), was covalently incorporated into thermoreversible Diels–Alder (DA) cross-linking networks. Mechanical activation of SPs in DA networks was confirmed […]