EurekAlert April 10, 2024 Researchers in China investigated isolated deep convections (IDCs), which have a smaller spatial and temporal size than mesoscale convective systems (MCSs), over the TP in the rainy season during 2001–2020. They showed that IDCs mainly concentrated over the southern Tibetan plateau (TP). The larger IDC had intense precipitation contributing 20 %–30 % to total precipitation, with a larger percentage in July and August than in June and September. IDCs contribute more to both total precipitation and extreme precipitation over the TP compared to the surrounding plain regions. IDCs over the TP account for a larger fraction […]
Magnetic fields boost clean energy
Nanowerk April 7, 2024 Magnetic field effects on electrocatalysis have recently gained attention due to the substantial enhancement of the oxygen evolution reaction (OER) on ferromagnetic catalysts. An international team of researchers (Switzerland, Argentina) used a specifically designed magneto-electrochemical system and non-magnetic electrodes to quantify magnetic field effects. They found marginal enhancement in reactions with high reactant availability, such as the OER, whereas substantial boosts exceeding 50% were observed in diffusion limited reactions, exemplified by the oxygen reduction reaction (ORR). According to the researchers their results advanced the fundamental understanding of magnetic fields in electrocatalysis and unveil new prospects for […]
Magnetic levitation: New material offers potential for unlocking gravity-free technology
Phys.org April 8, 2024 An international team of researchers (Japan, Taiwan, Mexico, Australia) demonstrated the passive, diamagnetic levitation of a centimeter-sized massive oscillator, which was fabricated ensuring that the material, though highly diamagnetic, was an electrical insulator. By chemically coating a powder of microscopic graphite beads with silica and embedding the coated powder in high-vacuum compatible wax, they formed a centimeter-sized thin square plate which magnetically levitated over a checkerboard magnet array. The insulating coating reduced eddy damping by almost an order of magnitude compared to uncoated graphite with the same particle size. The plates exhibited a different equilibrium orientation […]
New device gathers, stores electricity in remote settings
Science Daily April 9, 2024 Researchers at the University of Utah investigated a pyro electrochemical cell (PEC) as a novel device concept for direct conversion of thermal energy to stored electrochemical energy. The PEC integrated a porous, pyroelectric separator within a supercapacitor. The pyroelectric separator induced an electric field within the PEC when exposed to a temperature change with time. The electric field drove ions into electrode double layers to charge the cell. Experimental results were coupled with simulations to explore PEC response when thermally cycled, with predicted pyroelectric orientation effects observed in two tests. The pyroelectric separator showed a […]
New technique lets scientists create resistance-free electron channels
Science Daily April 9. 2024 Moiré systems made from stacked two-dimensional materials host correlated and topological states that can be electrically controlled with applied gate voltages. One prevalent form of topological state that can occur are Chern insulators that display a quantum anomalous Hall effect. An international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, Japan) manipulated Chern domains in an interaction-driven quantum anomalous Hall insulator made from twisted monolayer–bilayer graphene and observed chiral interface states at the boundary between different domains. By tuning the carrier concentration, they stabilized neighbouring domains of opposite Chern number that then […]
Old crystal, new story for enhancing deep ultraviolet laser performance
Phys.org April 1, 2024 Researchers in China obtained 60-mW solid-state deep ultraviolet (DUV) laser at 193 nm with narrow linewidth with two stages of sum frequency generation in lithium triborate (LBO) crystals. The pump lasers were derived from a homemade Yb-hybrid laser. The Yb-hybrid laser was power scaling by a 2mm×2mm×30mm Yb:YAG bulk crystal. The 220-mW DUV laser at 221 nm, and the 193-nm laser delivered an average power of 60 mW with a pulse duration of 4.6 ns. The conversion efficiency reached 27% for 221 to 193 nm and 3% for 258 to 193 nm. According to the researchers […]
Physicists discover a novel quantum state in an elemental solid
Phys.org April 10, 2024 The nexus of topology and interactions yield important research directions. Using tunnelling microscopy, photoemission spectroscopy and a theoretical analysis an international team of researchers (USA – Princeton University, University of Alabama at Birmingham, Florida State University, Oak Ridge National laboratory, UK, Singapore, China, Switzerland) has shown a “hybrid” topological phase of matter in elemental-solid arsenic. They showed that arsenic features a conjoined strong and higher-order topology that stabilizes a hybrid topological phase. Measurements unraveled a unique geometry of topologically induced step-edge conduction channels. Using theoretical models, they showed that the existence of gapless step-edge states in […]
Propagating dimensions of light: Deforming versatile non-diffractive beams along the optical trajectory
Phys.org April 8, 2024 Despite the numerous types of non-diffraction beam generation technologies, the 3D deformation and intricate wavefront shaping of structures during propagation have yet to be studied through the lens of nanophotonic devices. An international team of researchers (Singapore, Spain) demonstrated the dynamic conversion of a circular Airy beam (CAB) to a Bessel beam with a single-layer spin-selective metasurface. The spatial transformation developed from the interplay of 1D local and 2D global phases, facilitating the 3D control of non-diffractive light fields. Overall phase gradient and orbital angular momentum altered the propagation direction and transverse fields of complex amplitude […]
Quantum crystal of frozen electrons – the Wigner crystal – is visualized for the first time
Nanowerk April 10, 2024 A variety of two-dimensional systems have shown evidence for Wigner crystals (WCs), electrons crystallized into a closely packed lattice. However, a spontaneously formed classical or quantum WC has never been directly visualized. An international team of researchers (USA – Princeton University, UC Berkeley, Lawrence Berkeley National Laboratory, Japan) imaged a magnetic-field-induced electron WC in Bernal-stacked bilayer graphene and examined its structural properties as a function of electron density, magnetic field, and temperature. At high fields and the lowest temperature, they observed a triangular lattice electron WC in the lowest Landau level. The WC possessed the expected […]
The spontaneous emergence of 1D superconducting stripes at a 2D interface in an oxide heterostructure
Phys.org April 8, 2024 Magnetism can cause a modulation of superconducting pairing in real space in both copper-based and iron-based materials. Researchers in China reported on the discovery of a spatially varying superconducting state residing at the interface between KTaO3 and ferromagnetic EuO. Electrical transport measurements revealed different values of the critical temperature and magnetic field at which the superconductivity breaks down when current was applied along the two orthogonal in-plane directions. This anisotropy occurred in low-carrier-density samples that were characterized by strong coupling between the Ta 5d and Eu 4f electrons, whereas in high-carrier-density samples, the coupling was weakened, […]