Phys.org April 2, 2024 Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order, not possible in quantum Hall and Chern insulator systems. An international team of researchers (USA – Boston College, Harvard University, UCLA, Texas A&M, University of Tennessee, MIT, Singapore, Japan, China, Canada) has found a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrated the QSH insulator, manifesting enhanced nonlocal transport […]
Room-temperature 2D magnet: Electronic-structure insights
Nanowerk March 28, 2024 Iron gallium telluride (Fe3GaTe2), a van der Waals ferromagnet, demonstrated intrinsic ferromagnetism above room temperature. An international team of researchers (USA – Lawrence Livermore National Laboratory, South Korea, China) revealed the electronic structure of Fe3GaTe2 in its ferromagnetic ground state establishing a consistent correspondence between the measured band structure and theoretical calculations, underscoring the significant contributions of the Heisenberg exchange interaction (Jex) and magnetic anisotropy energy to the development of the high-TC ferromagnetic ordering in Fe3GaTe2. They observed substantial modifications to these crucial driving factors through doping, which they attributed to alterations in multiple spin-splitting bands […]
‘Shear sound waves’ provide the magic for linking ultrasound and magnetic waves
Phys.org March 29, 2024 An international team of researchers (Japan, Austria, Spain) observed strong coupling between magnons and surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an on-chip SAW resonator by analyzing SAW phonon dispersion ant crossings. They used a nanostructured SAW resonator design that allowed them to enhance shear-horizontal strain. This type of strain couples strongly to magnons. Their device design provided the tunability of the film thickness with a fixed phonon wavelength, which was a departure from the conventional approach in strong magnon-phonon coupling research. They detected a monotonic increase in the coupling strength […]
Simple equations clarify cloud climate conundrum
Phys.org April 1, 2024 Changes in anvil clouds with warming remain a leading source of uncertainty in estimating Earth’s climate sensitivity. An international team of researchers (France, UK) developed a feedback analysis that decomposes changes in anvil clouds and creates testable hypotheses for refining their proposed uncertainty ranges with observations and theory. They derived a simple but quantitative expression for the anvil area feedback, which depended on the present-day measurable cloud radiative effects and the fractional change in anvil area with warming. Satellite observations suggested an anvil cloud radiative effect of about ±1 W m−2, which requires the fractional change in anvil […]
A simple way to harvest more ‘blue energy’ from waves
Science Daily April 3, 2024 Due to the advantages of simple structure and flexibility for energy harvesting, the tube liquid–solid triboelectric nanogenerator (TLS-TENG) has attracted much attention. However, it is limited by low output power due to its low surface charge density and transfer efficiency. Researchers in China proposed and constructed TLS-TENG (SVE-TLS-TENG) with enhanced output performance. Through the space volume effect, the open-circuit voltage (Uoc), short-circuit current (Isc), and transfer charge (Qtc) of SVE-TLS-TENG they improved energy harvesting by 3.5 times, 2.3 times, and 2 times, respectively. The SVE-TLS-TENG has high output performance for harvesting low-frequency and high-entropy motion […]
A single photon emitter deterministically coupled to a topological corner state
Phys.org April 2, 2024 Researchers in China presented a single photon emitter that utilizes a single semiconductor quantum dot, deterministically coupled to a second-order topological corner state in a photonic crystal cavity. By investigating the Purcell enhancement of both single photon count and emission rate within this topological cavity, they got an experimental Purcell factor of Fp = 3.7. They demonstrated the on-demand emission of polarized single photons, with a second-order autocorrelation function g(2)(0) as low as 0.024 ± 0.103. According to the researchers their work may be used for customizing light-matter interactions in topologically nontrivial environments… read more. Open Access TECHNICAL ARTICLE
A solar cell you can bend and soak in water
RIKEN Research March 27, 2024 Waterproofing ultra flexible organic photovoltaics without compromising mechanical flexibility and conformability remains challenging. An international team of researchers (Japan, USA – Georgia Institute of Technology) demonstrated waterproof and ultra flexible organic photovoltaics through the in-situ growth of a hole-transporting layer to strengthen interface adhesion between the active layer and anode by depositing silver electrode directly on top of the active layers, followed by thermal annealing treatment. The in-situ grown hole-transporting layer exhibited higher thermodynamic adhesion between the active layers, resulting in better waterproof. The 3 μm-thick organic photovoltaics retained 89% and 96% of their pristine performance […]
Universal brain-computer interface lets people play games with just their thoughts
Science Daily April 1, 2024 Subject training requires collecting user-specific calibration data due to high inter-subject neural variability that limits the usability of generic decoders. Calibration is cumbersome and may produce inadequate data for building decoders, especially with naïve subjects. Researchers at UT Austin showed that a decoder trained on the data of a single expert is readily transferrable to inexperienced users via domain adaptation techniques allowing calibration-free Brain-computer interface (BCI) training. They introduced two real-time frameworks, (i) Generic Recentering (GR) through unsupervised adaptation and (ii) Personally Assisted Recentering (PAR) and evaluated it on naïve subjects to show that their […]
Breakthrough in light manipulation: Unveiling novel finite barrier bound states
Phys.org March 22, 2024 A boundary mode localized on one side of a finite-size lattice can tunnel to the opposite side which results in unwanted couplings and the tunneling probability decays exponentially with the size of the system which requires many lattice sites before eventually becoming negligibly small. An international team of researchers (USA – PNNL, China) showed that the tunneling probability for some boundary modes can apparently vanish at specific wavevectors and a boundary mode can be completely trapped within very few lattice sites where the bulk bandgap is not even well-defined. The number of trapped states equaled the […]
Top 10 Science and Technology Inventions for the Week of March 29, 2024
01. Electron-bending effect could boost computer memory 02. Moebius rings enable new ways to control light in twisted spaces 03. Quantum interference could lead to smaller, faster, and more energy-efficient transistors 04. Pushing back the limits of optical imaging by processing trillions of frames per second 05. Researchers harness the sun to produce hydrogen gas from water 06. Researchers take major step toward developing next-generation solar cells 07. The world is one step closer to secure quantum communication on a global scale 08. Engineers find a new way to convert carbon dioxide into useful products 09. New research area promotes […]