Phys.org February 1, 2024 Crystals spontaneously break the continuous translation symmetry of free space. An international team of researchers (Germany, Russia) demonstrated a robust continuous time crystal in an electron–nuclear spin system of a semiconductor tailored by tuning the material composition. Continuous, time-independent external driving of the sample produced periodic auto-oscillations with a coherence time exceeding hours. Varying the experimental parameters revealed wide ranges in which the time crystal remained stable. At the edges of these ranges, they found chaotic behaviour with a lifted periodicity corresponding to the melting of the crystal. According to the researchers time crystal state enabled […]
Tag Archives: Advanced materials
Researchers add a ‘twist’ to classical material design
Phys.org January 24, 2024 Epitaxial growth of a crystalline film normally proceeds from one substrate. Researchers at Stanford University expanded the concept of epitaxy to a regime of “twisted epitaxy” with the epilayer crystal orientation between two substrates influenced by their relative orientation. They annealed nanometer-thick gold nanoparticles between two substrates of exfoliated hexagonal molybdenum disulfide with varying orientation of their basal planes with a mutual twist angle ranging from 0° to 60°. For larger twist angles, Au had only a small misorientation with the bottom MoS2. Further revealed a periodic strain variation (<|±0.5%|) in the Au nanodisks associated with […]
New conductive, cotton-based fiber developed for smart textiles
Science Daily December 11, 2023 Blending conductive fillers with cellulose is the most common means of fiber production. Incorporating a high content of conductive fillers is necessary to achieve desirable conductivity. However, a high filler load deteriorates the processability and mechanical properties of the fibers. Researchers at Washington State University developed wet-spun cellulose-based fibers with a unique side-by-side (SBS) structure via sustainable processing. They engineered sustainable sources (cotton linter and post-consumer cotton waste) and a biocompatible intrinsically conductive polymer (i.e., polyaniline, PANI) into fibers containing two co-continuous phases arranged side-by-side… read more. TECHNICAL ARTICLE
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 […]
Topological materials open a new pathway for exploring spin hall materials
Science Daily September 21, 2023 One of the hallmarks of Magnetic Weyl semimetals (mWSMs) is the emergence of large intrinsic anomalous Hall effect. On heating the mWSM above its Curie temperature, the magnetism vanishes while exchange-split Weyl point pairs collapse into doubly degenerate gapped Dirac states. Researchers in Japan found potential of these Dirac nodes in paramagnetic state for efficient spin current generation at room temperature via the spin Hall effect. They introduced Ni and In to separately substitute Co and Sn in a prototypal mWSMCo3Sn2S2 shandite film and tuned the Fermi level. Composition dependence of spin Hall conductivity for […]
Transparent wood-based coating doesn’t fog up
Nanowerk September 26, 2023 Researchers in Finland developed a way to turn a waste material from wood into a bio-based transparent film that can be used for anti-fogging or anti-reflective coatings on glasses or vehicle windows. They prepared optically clear lignin nanoparticle dispersions from acetylated lignin. Thin lignin nanoparticle films remained transparent when deposited on glass and other smooth surfaces, and monolayered particle films provided effective antifogging properties. The particles could also be used to prepare multilayered films with bright structural colors that could be controlled via the film-thickness and were retained in dry conditions. They also developed an improved […]
Plumbing the depths of thermoelectrics in search of novel materials
Phys.org September 18, 2023 Although historically the thermoelectric effect was first discovered in metals, state-of-the-art research focuses on semiconductors. An international team of researchers (Austria, Japan) discovered unprecedented thermoelectric performance in metals and realized ultrahigh power factors in binary nickel and gold alloys, more than twice larger than in any bulk material above room temperature. In metallic NixAu1–x alloys, large Seebeck coefficients originated from electron-hole selective scattering of Au s electrons into more localized Ni d states. This intrinsic energy filtering effect owing to the unique band structure yielded a strongly energy-dependent carrier mobility. While the metastable nature of the […]
Researchers develop high-performance zero thermal expansion composite for precision devices
Phys.org September 14, 2023 Negative thermal expansion (NTE) materials can be applied to suppress thermal expansion of other materials, forming composites with zero thermal expansion (ZTE). However, the shortcomings (e.g., high density, narrow working temperature window) inherited from various NTE materials hinder the applications of corresponding ZTE composites. An international team of researchers (China, Poland) used modified Cu2P2O7 by reducing oxygen deficiencies, which had a relatively low density and strong NTE over a wide temperature range, to composite with 2024Al. When the volume content of modified Cu2P2O7 was about 50%, the composite Cu2P2O7/2024Al showed ZTE effect, and the linear coefficient […]
Scientists develop self-healing elastomer for flexible electronics
Phys.org September 18, 2023 The mechanical properties of the substrate elastomers are often poor due to the inherent performance of the materials. Researchers in China prepared a poly(vinyl alcohol) (PVA)-based self-healing material with high strength and good thermal stability by side-linked grafting modification of PVA with a one-step esterification reaction. Benefiting from the hydrogen bonds and ion coordination between iron ions and carboxyl groups, the synthesized elastomer exhibited excellent mechanical properties and good self-healing performance. The high sensitivity and self-healing performance of a silver nanowire-coated elastomer strain sensor demonstrated the wide potential applicability of the prepared PVA-based elastomers in health […]
A new design strategy for mechanoresponsive materials with high thermal tolerance
Phys.org September 11, 2023 Radical type mechanophores (RMs), molecules that can undergo small-scale chemical reactions upon exposure to a mechanical stimulus are studied due to their potential application in the fabrication of highly functionalized polymers. However, the lack of a rational design concept with pre-determined properties limits their development. Researchers in Japan have developed a rational design strategy of RMs with high thermal tolerance while maintaining mechanoresponsiveness. Through experimental and theoretical analysis, they found that the high thermal tolerance of RMs is related to the radical-stabilization energy (RSE) as well as the Hammett and modified Swain–Lupton constants at the para-position. […]