Nanowerk October 10, 2023 Assembling different TMD layers into vertical stacks creates a new artificial material called a van der Waals (vdW) heterostructure. By incorporating different materials, it becomes possible to combine the properties of individual layers, producing new optoelectronic devices with tailor-made properties. To understand the unusual stacking sequence, an international team of researchers (South Korea, Germany, USA – Oak Ridge National Laboratory) introduced the excitonic Elliot formula by imposing strain exclusively on the top layer that could be a consequence of the stacking process. They found that the intensity ratio of Q- to K-excitons in the same layer […]
Tag Archives: Advance materials
Scientists develop environmentally safe, frost-resistant coatings
Phys.org April 1, 2022 Researchers at the University of Illinois have proposed a design rationale for developing a family of cryoprotectant and phase change material-based compositions in the form of mixtures, non-aqueous emulsions-creams and gels. An in situ generated surface hydration layer protects the underlying substrate from a variety of foulants, varying from ice to disease-causing bacteria. Each formulation utilizes unique chemistry to curtail the embodied cryoprotectant loss and can be easily applied as an all-in-one sprayable/paintable coating capable of significantly outperforming untreated industrial materials in terms of their ability to delay condensation-frosting and shed ice simultaneously. They observed an […]
Optical tweezer technology tweaked to overcome dangers of heat
Phys.org June 26, 2021 The requirement of a strongly focused and high-intensity laser beam results in potential photon-induced thermal damages to target objects, including nanoparticles, cells, and biomolecules. Researchers at UT Austin have developed a new version of optical tweezers which exploit solid-state optical refrigeration and thermophoresis to trap particles and molecules at the laser-generated cold region. While laser refrigeration can avoid photothermal heating, the use of a weakly focused laser beam can further reduce the photodamages to the target object. The noninvasive optical tweezing technique will bring new possibilities in the optical control of nanomaterials and biomolecules for essential […]
Discovery of a mechanism for making superconductors more resistant to magnetic fields
Phys.org March 30, 2021 Researchers in Japan discovered that when the crystalline films of indium is thinned to a two-dimensional atomic layer, the spin, and the momentum of the electrons in the layer are coupled, causing the electron spins to frequently rotate. This offsets the effect of the changes in electronic energy induced by the magnetic field and thus preserves superconductivity. This mechanism can enhance the critical magnetic field up to 16-20 Tesla, which is approximately triple the generally accepted theoretical value. It is expected to have a wide range of applications as it was observed for an ordinary superconducting […]
Experimental evidence of an intermediate state of matter between a crystal and a liquid
EurekAlert January 19, 2021 Researchers in Russia present a detailed analysis of their experimental study, which shows clear evidence of a two-stage melting process of a quasi-two-dimensional dusty plasma system in a high-frequency gas discharge. They accurately calculated global parameters of the orientational and translational order, as well as their susceptibilities to determine two critical points, related to “solid-to-hexatic” and “hexatic-to-liquid” phase transitions. The nature of the emerging defects and changes in their mutual concentration, in addition to the estimate of core energy of free dislocations also counts in favor of the formation of an intermediate hexatic phase. These results […]
New evidence that the quantum world is even stranger than we thought
Nanowerk September 7, 2020 Researchers at Purdue University have shown that anyons exhibit fractional charge and fractional statistics that maintain a “memory” of their interactions with other quasiparticles by inducing quantum mechanical phase changes. They demonstrated this behavior by routing the electrons through a specific maze-like etched nanostructure made of gallium arsenide and aluminum gallium arsenide. The interferometer confined the electrons to move in a two-dimensional path. When the device was cooled to within one-hundredth of a degree from absolute zero and subjected to a powerful 9-Tesla magnetic field. the electrical resistance of the interferometer generated an interference pattern which […]
Scientists develop novel transparent broadband electromagnetic interference shielding materials
Phys.org July 27, 2020 Electromagnetic interference shielding materials are visibly opaque. Researchers in China proposed and fabricated visibly transparent EMI shielding materials using an ultrathin silver layer sandwiched by oxides (SLSO) as building blocks. The structure exhibited the highest EMI shielding effectiveness (SE) of 70 dB at 27.6 GHz (>62 dB on average at 4–40 GHz) and a transmittance close to 90% at a visible wavelength of 550 nm, which is comparable with those of polyethylene terephthalate (PET) and glass substrates. The D-SLSO structure suppresses optical reflections as antireflection coatings and enhances EMI shielding via Fabry–Pérot interference. They describe other […]