Phys.org April 27, 2022 Molybdenum disulfide (MoS2) is known as one of the most promising and robust 2D electronic materials. However, despite theoretical predictions, no ferroelectricity has been experimentally detected in MoS2. An international team of researchers (USA – University of Nebraska, industry, China, France, Luxembourg) has reported the experimental observation of a stable room-temperature out-of-plane polarization ordering in 2D MoS2 layers, where polarization switching is realized by mechanical pressure induced by a tip of a scanning probe microscope. Using this approach, they created the bi-domain polarization states, which exhibit different piezoelectric activity, second harmonic generation, surface potential, and conductivity. […]
Thin quantum wires work better with less insulating coatings
Phys.org May 4, 2022 Thin semiconducting wires, referred to as quantum wires, are often coated in insulating materials. Previous studies have explored how the mismatch between the insulating properties of both materials can influence their performance. Researchers in Vietnam have shown that thinner wires with less insulating coatings can improve the mobility of the electrons they carry. Previous models have presented conflicting conclusions about the ability of electrons to move through the wire, depending on whether coatings are more or less insulating than the semiconductor. The researchers considered the case where electrons are allowed to cross the outer boundary of […]
A simpler approach for creating quantum materials
Phys.org May 4, 2022 Using twisted bilayer graphene to make devices remains challenging because of the low yield of fabricating twisted bilayer graphene. Researchers at the University of Pennsylvania have shown how patterned, periodic deformations of a single layer of graphene transforms it into a material with electronic properties previously seen in twisted graphene bilayers. To better understand the quantum geometrical properties of this system, they set out to understand the theory underlying how electrons move in this single-layered system. After running computer simulations of single-layered experiments, the researchers were surprised to find new evidence of unexpected phenomena along the […]
Zero-index metamaterials offer new insights into the foundations of quantum mechanics
Phys.org April 27, 2022 Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. An international team of researchers (USA – Harvard University, University of Pennsylvania, Belgium, Spain, Denmark) re-examined the foundations of quantum physics from the perspective of momentum and explored what happens when the momentum of light is reduced to zero. They theoretically demonstrated that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZI materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZI […]
Top 10 Science and Technology Inventions for the Week of April 29, 2022
01. Breakthrough for efficient and high-speed spintronic devices 02. DARPA Seeks Ionospheric Insights to Improve Communication Across Domains 03. New hardware integrates mechanical devices into quantum tech 04. A novel insulating state emerges in a 2D material 05. Researchers create exotic magnetic structures with laser light 06. Researchers develop a paper-thin loudspeaker 07. Scientists turn a hydrogen molecule into a quantum sensor 08. Two teams use neutral atoms to create quantum circuits 09. Unexpected light behavior may be harnessed to improve optical communications and sensors 10. A new guide to extremely powerful light pulses And others… China detects first human […]
Breakthrough for efficient and high-speed spintronic devices
Science Daily April 25, 2022 How the spin evolves in the nanoworld on extremely short time scales, in one millionth of one billionth of a second, has remained largely mysterious. An international team of researchers (Austria, Canada, Germany, Switzerland, France, China) used a tabletop ultrafast soft X-ray microscope based on a high-energy Ytterbium laser to spatio-temporally resolve the spin dynamics inside rare earth materials. They recorded a series of snapshot images of the nanoscale rare earth magnetic structures providing rich information on the magnetic properties that are as accurate as those obtained using large-scale X-ray facilities. According to the researchers […]
China detects first human case of H3N8 bird flu
MedXpress April 27, 2022 H3N8 is known to have been circulating since 2002 after first emerging in North American waterfowl. It is known to infect horses, dogs, and seals, but has not previously been detected in humans. China’s National Health Commission on Tuesday said a four-year-old boy living in central Henan province tested positive for the strain after being hospitalized earlier this month with a fever and other symptoms. The boy was infected directly by birds and the strain was not found to have “the ability to effectively infect humans”, the commission said. The H5N1 and H7N9 strains of bird […]
Climate change triggering global collapse in insect numbers, stressed farmland shows 63% decline: New research
Phys.org April 21, 2022 Although research has shown that biodiversity changes are driven primarily by land-use change and increasingly by climate change, the potential for interaction between these drivers and insect biodiversity on the global scale remains unclear. Researchers in the UK have shown that the interaction between indices of historical climate warming and intensive agricultural land use is associated with reductions of almost 50% in the abundance and 27% in the number of species within insect assemblages relative to those in less-disturbed habitats with lower rates of historical climate warming. These patterns are particularly evident in the tropical realm. […]
DARPA Seeks Ionospheric Insights to Improve Communication Across Domains
DARPA April 22, 2022 DARPA’s new Ouija program aims to use sensors on low-orbiting satellites to provide new insights into HF radio wave propagation in the ionosphere. Ouija will augment ground-based measurements with in-situ measurements from space, in very low- Earth orbit (VLEO), to develop and validate accurate, near real-time HF propagation predictions. The VLEO altitude regime is of particular interest due to its information-rich environment where ionospheric electron density is at a maximum. The program includes two technical areas. The first technical area announced in a solicitation, seeks to develop, qualify, launch, and operate multiple small satellites carrying scientific […]
Insights narrow the gap between large-scale atmospheric models and microscale features of atmospheric winds
Phys.org April 26, 2022 Modeling anomalies referred to as grey zone, arise when the model resolution approximates the length scale of turbulence features while modeling the atmosphere. An international team of researchers (USA – Notre Dame, Saudi Arabia) leveraged a new set of one-way nested, full-physics multiscale numerical experiments to quantify the magnitude of the errors introduced at gray zone resolutions in a real-case application. The new set of experiments conducted in Saudi Arabia spanned a wide range of scales and strategies to suppress resolved convection at gray zone resolutions. Detailed analyses of their experiments showed that (i) grid-dependent convective […]