Nanowerk August 17, 2023 Slippery covalently attached liquid surfaces (SCALS) with low contact angle hysteresis (CAH) and nanoscale thickness display impressive anti-adhesive properties, like lubricant-infused surfaces. Their efficacy is generally attributed to the liquid-like mobility of the constituent tethered chains. However, the precise physico-chemical properties that facilitate this mobility are unknown. An international team of researchers (Australia, Germany) quantified the chain length, grafting density, and microviscosity of a range of polydimethylsiloxane (PDMS) SCALS, elucidating the nanostructure responsible for their properties. They used three methods to produce SCALS, with characterization carried out via single-molecule force measurements, neutron reflectometry, and fluorescence correlation […]
Category Archives: Materials science
Scientists trap light inside a magnet
Science Daily August 16, 2023 Recent studies were able to modify some of the most defining features of light utilizing the strong coupling of light and matter in optical cavities. An international team of researchers (City College of New York, City University of New York, University of Washington, University of Michigan, MIT, Spain) studied the magneto-optical properties of a van der Waals magnet that supports strong coupling of photons and excitons even in the absence of external cavity mirrors. In the layered magnetic semiconductor CrSBr polaritons were shown to substantially increase the spectral bandwidth of correlations between the magnetic, electronic, […]
‘Topological gardening’ to achieve unexpected spin transport
Nanowerk August 22, 2023 In topological materials the interaction between the bulk state and edge states can be tuned to manipulate edge transport behavior, especially in topological crystalline insulators (TCI) which have multiple degrees of topological protection. This can open opportunities for novel electronic and spintronic applications. Researchers in Australia investigated how bulk-edge interactions can influence the edge transport in planar bismuthene, a TCI with metallic edge states protected by in-plane mirror symmetry. By exploring the impact of various perturbation effects, such as device size, substrate potentials, and applied transverse electric field, they examined the evolution of the electronic structure […]
Chromium replaces rare and expensive noble metals
Science Daily August 14, 2023 Researchers in Switzerland developed chromium compounds, very similar to those used in the past, that can replace the noble metals osmium and ruthenium. When irradiated with a red lamp the new chromium compounds the energy from the light could be stored in molecules which could serve as power source. They demonstrated it by building the chromium compounds into a stiff organic molecular framework consisting of carbon, nitrogen, and hydrogen. The stiff framework ensured that the chromium atoms were well packaged. The tailor-made environment minimized energy losses due to undesired molecular vibrations and to optimize the […]
From light to motion: Shaping surfaces with light
Nanowerk August 12, 2023 Using confocal microscopy researchers in Finland characterized dynamic photoinduced wrinkle erasure enabled by photomechanical changes in supramolecular polymer-azo complexes. Different photoactive molecules were compared to 4-hydroxy-4′-dimethylaminoazobenzene (OH-azo-DMA). The characteristic erasure times of wrinkles were assessed by using an image processing algorithm. The results confirmed that the photoinduced movement on the topmost layer could be successfully transferred to the substrate. Furthermore, the chosen supramolecular strategy allowed decoupling the effect of molecular weight of the polymer and photochemistry of the chromophore, allowing quantitative comparison of wrinkling erasure efficiency of different materials and providing a facile way to optimize […]
Nanomaterial offers new way to control fire
Nanowerk August 14, 2023 High-temperature flames can be difficult to control how it interacts with the material being processed. An international team of researchers (USA – Iowa State University, North Carolina State University, Ames National Laboratory, Canada) developed a technique that utilizes a molecule-thin protective layer to control how the flame’s heat interacts with the material allowing users to finely tune the characteristics of the processed material. They pyrolyzed alkysilanes grafted onto cellulose fibers into non-flammable SiO2 terminating surface ignition propagation, hence stalling flame propagating. Sustaining high temperatures, however, triggered gnition in the bulk of the fibers but under restricted […]
New property of hydrogen predicted
Phys.org August 7, 2023 Recently it was predicted based on ab initio quantum Monte Carlo simulations that, in a uniform electron gas, the peak ω0 of the dynamic structure factor S(q,ω) exhibits an unusual nonmonotonic wave number dependence, where dω0/dq<0, at intermediate q, under strong coupling conditions. Researchers in Germany predicted that this nonmonotonic dispersion resembling the roton-type behavior known from superfluids should be observable in a dense, partially ionized hydrogen plasma. Based on a combination of path integral Monte Carlo simulations and linear response results for the density response function, they presented the approximate range of densities, temperatures and […]
Potential application of unwanted electronic noise in semiconductors
Science Daily August 10, 2023 Random noise in magnetic materials is of potential use in systems such as spiking neuron devices, random number generators and probability bits. An international team of researchers (South Korea, China, USA – Harvard University, Montana State University) has shown electrically tunable magnetic fluctuations and random telegraph noise in multilayered vanadium-doped tungsten diselenide (WSe2) using vertical tunnelling heterostructure devices composed of graphene/vanadium-doped WSe2/graphene and magnetoresistance measurements. They identified bistable magnetic states through discrete Gaussian peaks in the random telegraph noise histogram and the 1/f2 features of the noise power spectrum. Three categories of fluctuation were detected: […]
Scientists discover novel way of reading data in antiferromagnets, unlocking their use as computer memory
Nanowerk August 14, 2023 The Berry curvature and quantum metric are the imaginary part and real part, respectively, of the quantum geometric tensor which characterizes the topology of quantum states. The former is known to generate a zoo of important discoveries such as quantum Hall effect and anomalous Hall effect (AHE), while the consequences of the quantum metric have rarely been probed by transport. An international team of researchers (Singapore, Israel, China, Japan) has found quantum metric-induced nonlinear transport, including both nonlinear AHE and diode-like nonreciprocal longitudinal response, in thin films of a topological antiferromagnet, MnBi2Te4. They have revealed that […]
New method simplifies the construction process for complex materials
MIT News August 2, 2023 Cellular metamaterials are small scale, tileable structures that can be architected to exhibit many useful material properties. But their “architectures” vary widely making it difficult to explore them using existing representations. An international team of researchers (USA – MIT, Austria) created a technique to include many different building blocks of cellular metamaterials into one, unified graph-based representation using which engineers can quickly and easily model metamaterials, edit the structures, and simulate their properties. Their procedural graph succinctly represents the construction process for any structure using a simple skeleton annotated with spatially varying thickness. To express […]