Phys.org June 19, 2024 A spintronic THz emitter consisting of a ferromagnetic/nonmagnetic bilayer heterostructure is a promising innovation that can provide an alternative solution/replacement for conventional THz emitters. To extend the applicability of THz waves researchers in Japan developed and demonstrated an efficient and strong THz emission from a single layer of Co2MnGa with a large anomalous Hall effect (AHE) influenced by its Weyl semimetallic nature. They showed strong correlations among the THz emission, AHE, and chemical ordering of the full Heusler crystal structures for Co2MnGa. Based on proper structural and chemical design, the topological nature of this material facilitates […]
Tag Archives: S&T Japan
Quantum data assimilation: A quantum leap in weather prediction
Science Daily June 13, 2024 In the context of numerical weather prediction (NWP), data assimilation is particularly vital for improving initial conditions and subsequent predictions. However, the computational demands imposed by conventional approaches, pose notable challenges in computational time. Researchers in Japan proposed quantum data assimilation approach which solves the data assimilation problem using quantum annealers. Their experiments using the 40-variable Lorenz model were highly promising, showing that the quantum annealers produced an analysis with comparable accuracy to conventional data assimilation approaches. In particular, the D-Wave Systems physical quantum annealing machine achieved a significant reduction in execution time… read more. […]
Towards next-gen functional materials: direct observation of electron transfer in solids
Science Daily June 4, 2024 Nanoscale electron transfer (ET) in solids is fundamental to the design of multifunctional nanomaterials, yet its process is not fully understood. Researchers in Japan directly observed solid-state ET via a crystal-to-crystal process. They first demonstrated the creation of a robust and flexible electron acceptor/acceptor (A/A) double-wall nanotube crystal with a large window through the one-dimensional porous crystallization of heteroleptic Zn4 metallocycles with two different acceptor ligands. They constructed the electron donor incorporated-A/A nanotube crystal through the subsequent absorption of electron donor guests. They removed electrons from the electron donor guests inside the nanotube crystal through […]
Researchers develop compiler acceleration technology for quantum computers
Phys.org May 9, 2024 Researchers in Japan used a random search technique to find quantum gate sequences that implement perfect quantum state preparation or unitary operator synthesis with arbitrary targets. The approach was based on the recent discovery that there is a large multiplicity of quantum circuits that achieved unit fidelity in performing a given target operation, even at the minimum number of single-qubit and two-qubit gates needed to achieve unit fidelity. They showed that the fraction of perfect-fidelity quantum circuits increased rapidly as soon as the circuit size exceeded the minimum circuit size required for achieving unit fidelity. This […]
Transforming common soft magnets into a next-generation thermoelectric conversion materials by 3 minutes heat treatment
Science Daily May 9, 2024 Nernst effect, a promising transverse thermoelectric phenomenon for energy harvesting and heat sensing, has been challenging to utilize due to the scarcity of materials with large anomalous Nernst coefficients. Researchers in Japan have shown how nanostructure engineering enables transforming simple magnetic alloys into spin-caloritronic materials displaying significantly large transverse thermoelectric conversion properties. They demonstrated a remarkable ~ 70% improvement in the anomalous Nernst coefficients and a significant enhancement in the power factor in flexible Fe-based amorphous materials by nanostructure engineering without changing their composition. This surpassed all reported amorphous alloys and was comparable to single crystals showing large […]
Artificial muscles with embedded bifurcation structures can control complex motion
Science Daily April 27, 2024 Harnessing complex body dynamics is a challenge in robotics, particularly when dealing with soft dynamics, which exhibit high complexity in interacting with the environment. Recent studies indicate that these dynamics can be used as a computational resource. Researchers in Japan demonstrated that bifurcations, including periodic and chaotic dynamics, could be embedded into the pneumatic artificial muscle, with the entire bifurcation structure using the framework of physical reservoir computing. Their results suggested that dynamics not present in training data could be embedded through bifurcation embedment, implying the capability to incorporate various qualitatively different patterns into pneumatic […]
Revolutionizing memory technology: multiferroic nanodots for low-power magnetic storage
Nanowerk April 26, 2024 Researchers in Japan fabricated nanodots composed of multiferroic cobalt-substituted BiFeO3, a ferroelectric ferromagnet at room temperature, by pulsed laser deposition using anodized porous alumina as masks. The nanodots were approximately 60 nm in diameter, more than 10 nm in thickness, and approximately 70 Gbit/in.2 in density. They showed both ferroelectricity and ferromagnetism with a single-domain nature. They found that the dot with 190 nm diameter had multidomain vortex ferroelectric and magnetic structures indicating the strong magnetoelectric coupling. The single-domain cobalt-substituted BiFeO3 nanodots were suitable for verifying magnetization reversal by the electric field, which was the first […]
A 2D ‘antenna’ boosts light emission from carbon nanotubes
Phys.org March 22, 2024 Nanomaterials exhibit excitonic quantum processes occurring at room temperature. However, low dimensionality imposes strict requirements for conventional optical excitation. Researchers in Japan found that exciton transfer in carbon-nanotube/tungsten-diselenide heterostructures occur when alignment could be systematically varied. The mixed-dimensional heterostructures displayed a pronounced exciton reservoir effect where the longer-lifetime excitons within the two-dimensional semiconductor were funneled into carbon nanotubes through diffusion. The new excitation pathway presented several advantages, including larger absorption areas, broadband spectral response, and polarization-independent efficiency. When band alignment was resonant, they observed substantially more efficient excitation via tungsten diselenide compared to direct excitation of […]
Photon-like electrons in a four-dimensional world discovered in a real material
Phys.org March 14, 2024 Because of their differences from standard electrons, Dirac electrons are expected to add unprecedented electronic properties to materials. Researchers in Japan discovered a method enabling selective observation of the Dirac electrons in materials. Using electron spin resonance, to directly observe unpaired electrons in materials to distinguish differences in character, they established a method to determine their scope of action in the materials and their energies. They showed that electron spin resonance revealed that α-ET2I3 (ET = bis(ethylenedithio)-tetrathiafulvalene) at 1 bar contained a nearly three-dimensional DFs above ∼100 K coexisting with standard fermions. The close charge-transfer ET–I3 […]
Projection mapping leaves the darkness behind
Phys.org March 18, 2024 Projection mapping (PM) typically requires a dark environment to achieve high-quality projections, limiting its practicality. Researchers in Japan overcame this limitation by replacing conventional room lighting with heterogeneous projectors. These projectors replicated environmental lighting by selectively illuminating the scene, excluding the projection target. They developed distributed projector optimization framework designed to effectively replicate environmental lighting and incorporated a large-aperture projector, in addition to standard projectors, to reduce high-luminance emitted rays and hard shadows. To validate their approach, they conducted a series of quantitative and qualitative experiments. They successfully demonstrated that their projector-based lighting system significantly enhanced […]