Phys.org November 24, 2020 THz absorbers with strong absorption, broad-band absorption bandwidth and tunable characteristics have attracted the attention of many researchers with extensive application prospects in THz wave shielding, THz imaging, and THz sensitive thermal detecting. Researchers in China introduced strongly correlated electron material VO2 as a functional layer and realized the broad-band tunable THz spectrum properties in the device. The conductivity, dielectric constant, as well as optical properties got a dramatic switching during the insulator-metal transition at TC = 340 K, and the transition could be tuned by temperature, electric field, and light. The device had a 74% […]
Tag Archives: Advanced materials
Topological mechanical metamaterials go beyond Newton’s third law
Phys.org November 19, 2020 An international team of researchers (Israel, Los Alamos) found a way to mimic non-Newtonian behavior in mechanical systems, and thereby develop a mechanical implementation for some of the more intractable topological quantum systems, which may offer fundamentally new insights into both the mechanical and quantum topological systems. The unit cells in a mechanical lattice are subjected to active feedback forces that are processed through autonomous controllers, pre-programmed to generate the desired local response in real-time. They demonstrated that the required topological phase, characterized by chiral edge modes, can be achieved in an analogous mechanical system only […]
Scientists Discover Exotic New Mineral Forged in The Furnace of a Russian Volcano
Science Alert November 18, 2020 The ‘Great Tolbachik Fissure Eruption’ of 1975–1976, and a second, lesser follow-up that took place between 2012–2013 opening rocky terrain to 130 unknown minerals which were identified. researchers in Russia have identified the latest one, petrovite, a sulfate mineral that takes shape as blue globular aggregates of tabular crystals, many holding gaseous inclusions. The copper atom in the crystal structure of petrovite has an unusual and rare coordination of seven oxygen atoms. At the chemical level, petrovite represents a new type of crystal structure. Its molecular framework – consisting of oxygen atoms, sodium sulphur and […]
Laying the groundwork for ultra-thin, energy efficient photodetector on Gorilla glass
Nanowerk November 2, 2020 Direct growth of high-performance, scalable, and reliable electronic materials on glass is difficult owing to low thermal budget. Researchers at the Pennsylvania State University have addressed the issue by relatively low-temperature (<600 °C) metal–organic chemical vapor deposition growth of atomically thin MoS2 on multicomponent glass and fabrication of low-power phototransistors using atomic layer deposition (ALD)-grown, high-k, and ultra-thin Al2O3 as the top-gate dielectric, circumventing the challenges associated with the ALD nucleation of oxides on inert basal planes of van der Waals materials. The MoS2 photodetectors demonstrate the ability to detect low-intensity visible light at high speed […]
On-surface synthesis of graphene nanoribbons could advance quantum devices
Nanowerk October 26, 2020 The lack of atomic-scale precision in using current state-of-the-art “top-down” synthetic methods — cutting a graphene sheet into atom-narrow strips – stymie graphene’s practical use. An international team of researchers (USA – Oak Ridge National Laboratory, The University of Tennessee, Poland, Luxembourg) has developed a “bottom-up” approach — building the graphene nanoribbon directly at the atomic level in such a way that it can be used in specific applications. The nanoribbons were synthesized on the surface of rutile titanium dioxide that assisted the cyclode-hydrofluorination of specifically designed precursor molecules through a series of thermally triggered transformations. […]
Room-temperature superconductor? Rochester lab sets new record toward long-sought goal
University of Rochester October 14, 2020 A team of researchers in the US (University of Rochester, industry, University of Nevada) reported superconductivity in a photochemically transformed carbonaceous sulfur hydride system, starting from elemental precursors, with a maximum superconducting transition temperature of 287.7 ± 1.2 kelvin (about 15 degrees Celsius) achieved at 267 ± 10 gigapascals. The superconducting state was observed over a broad pressure range in the diamond anvil cell. Superconductivity was established by the observation of zero resistance, a magnetic susceptibility of up to 190 gigapascals, and reduction of the transition temperature under an external magnetic field of up […]
Intelligent nanomaterials for photonics
Science Daily October 7, 2020 2D materials – combined with optical fibers – can enable novel applications in the areas of sensors, non-linear optics, and quantum technologies. An international team of researchers (Germany, Australia) studied the chemical vapor deposition of monolayer MoS2 and WS2 crystals on the core of microstructured exposed‐core optical fibers and their interaction with the fibers’ guided modes. Two distinct application possibilities of 2D‐functionalized waveguides to exemplify their potential are demonstrated. First, the excitonic 2D material photoluminescence is simultaneously excited and collected with the fiber modes. Then it is shown that third‐harmonic generation is modified by the highly […]
Scientists synthesise a MOF capable of degrading nerve agents in water
Nanowerk September 30, 2020 An international team of researchers (Spain, USA – Scripps research, CA, industry, UK, Portugal) used heterometallic metal-organic frameworks to exemplify the advantages of controlling metal distribution across the framework in heterogeneous catalysis by exploring their activity toward the degradation of a nerve agent simulant of Sarin gas. MUV-101(Fe) is the only pristine MOF capable of catalytic degradation of diisopropyl-fluorophosphate (DIFP) in non-buffered aqueous media. This activity cannot be explained only by the association of two metals, but to their synergistic cooperation, to create a whole that is more efficient than the simple sum of its parts. […]
Superconductivity with a twist explained
Phys.org September 29, 2020 An international team of researchers (Switzerland, Spain, the Netherlands, Italy, Japan) has shown that the interplay between the two hexagonal carbon lattices, slightly twisted, causes a much larger hexagonal moiré pattern to emerge. By creating this new periodicity, the interaction between the electrons changes, yielding “slow” electrons enabling superconductivity. At a temperature of 1.7 Kelvin, twisted bilayer graphene conducts electricity without resistance. The researchers have finally confirmed the mechanism behind these fascinating new superconductors…read more. TECHNICAL ARTICLE
New type of superconductor identified
Science Daily September 21, 2020 Strontium ruthenate (Sr2RuO4) has stood as the leading candidate for a spin-triplet superconductor for 26 years. Using resonant ultrasound spectroscopy an international team of researchers (USA – Cornell University, Florida State University, Germany, Japan) measured the entire symmetry-resolved elastic tensor Sr2RuO4 through the superconducting transition. They found a thermodynamic discontinuity in the shear elastic modulus which implies that the superconducting order parameter has two components, a two-component p-wave order parameter. As this order parameter appears to have been precluded by recent NMR experiments, they suggest that two other two-component order parameters are now the prime […]