Nanowerk November 3, 2022 By performing measurements on bulk graphite, and on epitaxial graphene films on SiC with different stacking orders and twisting, as well as in the presence of intercalated hydrogen an international team of researchers (USA – New York University, Italy, Czech Republic) found that the interfacial transverse shear modulus was critically controlled by the stacking order and the atomic layer–substrate interaction. They demonstrated that the modulus is a pivotal measurable property to control and predict sliding friction in supported two-dimensional materials. Their experiments demonstrated a reciprocal relationship between friction force per unit contact area and interfacial shear […]
Engineers develop a low-cost, quantum-dot-enhanced terahertz camera
Nanowerk November 5, 2022 The currently available THz detectors are limited in many aspects of their performance, including sensitivity, speed, bandwidth, and operating temperature. Most do not allow the characterization of THz polarization states. The recent observation of THz-driven luminescence in quantum dots offers a possible detection mechanism via field-driven interdot charge transfer. An international team of researchers (USA – MIT, University of Minnesota, , Stanford University, SLAC National Accelerator Laboratory, South Korea) has demonstrated a room-temperature CMOS THz camera and polarimeter based on quantum-dot-enhanced THz-to-visible upconversion mechanism with optimized luminophore geometries and fabrication designs. Besides broadband and fast responses, […]
Erbium atoms in silicon: A prime candidate for quantum networks
Phys.org November 7, 2022 A major challenge for a scalable architecture for quantum information processing is based on emitters in nanostructures that are coupled by light. Researchers in Germany demonstrated the integration of erbium atoms with special optical properties into a silicon crystal. Thus, the atoms could be connected by light at a wavelength that is commonly used in telecommunications, making them ideal building blocks for future quantum networks that enable calculations with several quantum computers, as well as the secure exchange of data in a quantum internet. They achieved a narrow inhomogeneous broadening, less than 1 GHz, strong optical […]
Faster and more efficient computer chips thanks to germanium
Science Daily November 8, 2022 The compound semiconductor silicon-germanium has decisive advantages over today’s silicon technology in terms of energy efficiency and achievable clock frequencies. But establishing contacts between metal and semiconductor on a nanoscale in a reliable way is the main problem with a high proportion of germanium than with silicon. An international team of researchers (Austria, Switzerland, France) found a method to create perfect interfaces between aluminium contacts and silicon germanium components on an atomic scale. They produced a thin silicon layer and the silicon-germanium. By heating the structure in a controlled manner a contact was created between […]
How to end COVID-19 as a public health threat
Science Daily November 3, 2022 An international team of researchers from 112 countries has recommend specific actions to end the persistent global threat to public health. The panel developed a set of 41 consensus statements and 57 recommendations to governments, health systems, industry, and other key stakeholders across six domains: communication; health systems; vaccination; prevention; treatment and care; and inequities. The highest-ranked recommendations call for the adoption of whole-of-society and whole-of-government approaches, while maintaining proven prevention measures using a vaccines-plus approach that employs a range of public health and financial support measures to complement vaccination. Other recommendations with at least […]
Low-loss, chip-scale programmable silicon photonic processor
Phys.org November 7, 2022 Silicon photonics has unique advantages of ultra-high integration density as well as CMOS compatibility, and thus makes it possible to develop large-scale programmable optical signal processors. However, the high silicon waveguides propagation losses and the high calibration complexity for all tuning elements due to the random phase errors is a challenge. An international team of researchers (China, USA – Industry) demonstrated a programmable silicon photonic processor by introducing low-loss multimode photonic waveguide spirals and low-random-phase-error Mach-Zehnder switches. The waveguide spirals were designed to be as wide as 2 µm, enabling an ultralow propagation loss of 0.28 […]
Magnetism or no magnetism? The influence of substrates on electronic interactions
Nanowerk November 9, 2022 While technological developments of 2D MOFs typically take advantage of substrates for growth, support, and electrical contacts, investigations often ignore substrates and their dramatic influence on electronic properties. Researchers in Australia have shown how substrates alter the correlated magnetic phases in Kagome MOFs using systematic density functional theory and mean-field Hubbard calculations. They demonstrated that MOF-substrate coupling, MOF-substrate charge transfer, strain, and external electric fields are key variables, activating and deactivating magnetic phases in these materials. They used the Kagome-arranged 9,10-dicyanoanthracene molecules coordinated with copper atoms as an example. According to the researchers their findings can […]
New technology creates carbon neutral chemicals out of thin air
Nanowerk November 9, 2022 An international team of researchers (UK, Spain) has demonstrated the feasibility of a Dual Function Material’s (DFM) ability to passively capture CO2 directly from the air opening the possibilities of chemical production from dilute sources of CO2, through a combination of CO2 adsorption and subsequent chemical transformation. Combinations of Ni Ru bimetallic catalyst with Na2O, K2O or CaO adsorbent were supported on CeO2–Al2O3 to develop flexible DFMs. They were shown to reversibly adsorb CO2 between the 350 and 650 °C temperature range and were easily regenerated by an inert gas purge stream. Captured CO2 could be […]
Novel copper gas penetration electrode can efficiently reduce CO2 to multicarbon products
Phys.org November 8, 2022 Although considerable progress has been made in CO2 electroreduction, sustained production of multicarbon compounds at high current density remains a challenge. Researchers in China reported a hierarchical micro/nanostructured Cu(100)-rich copper hollow fiber as a gas penetration electrode (GPE) that reduces CO2 to C2+ product with a faradaic efficiency of 62.8% and a current density of 2.3 A cm-2 in 0.5 M KHCO3 solution at −1.94 V (vs. RHE). Electrochemical results demonstrate that optimized mass transfer and enhanced three-phase interface reaction synergistically promote CO2 activation and reduction kinetics. Theoretical calculations suggested that the Cu(100) facet of Cu […]
Seeing clearly into a new realm—researchers prototype a new generation of quantum microscopy
Phys.org November 7, 2022 Quantum microscopes for probing material properties and physical processes have relied on quantum defects hosted in rigid, three-dimensional (3D) crystals such as diamond, limiting their ability to closely interface with the sample. An international team of researchers (Australia, China) built a prototype quantum microscope embedding point defects within a thin layer of the van der Waals material hexagonal boron nitride. To show the multi-modal capabilities of this platform, they assembled two different heterostructures of a van der Waals material in combination with a quantum-active boron nitride flake and demonstrated time-resolved, simultaneous temperature and magnetic imaging near […]