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 […]
Author Archives: Hema Viswanath
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 […]
Quantum dance to the beat of a drum: Researchers observe how energy of single electron is tuned by surrounding atoms
Phys.org March 14, 2024 Direct observation of the relevant interplay of the electronic structure of a single defect with other microscopic elementary excitations on their intrinsic length, time and energy scales has not been achieved. Researchers in Germany directly resolved in space, time, and energy how a spin–orbit-split energy level of an isolated selenium vacancy in a moiré-distorted WSe2 monolayer evolved under the controlled excitation of lattice vibrations. By locally launching a phonon oscillation and taking ultrafast energy-resolved snapshots of the vacancy’s states faster than the vibration period, they directly measured the impact of electron–phonon coupling in an isolated single-atom […]
Researchers achieve >99% photoluminescence quantum yield in metal nanoclusters
Phys.org March 18, 2024 Metal nanoclusters have emerged as NIR–emissive materials, but their room-temperature photoluminescence quantum yield (PLQY), especially in solution, is often low. Researchers in China studied the photophysics of Au22(tBuPhC≡C)18 (Au22) and its alloy counterpart Au16Cu6(tBuPhC≡C)18 (Au16Cu6) (where tBu is tert-butyl and Ph is phenyl) and found that copper doping suppressed the nonradiative decay and promoted intersystem crossing rate ~300-fold higher. According to the researchers their approach could enable the development of highly emissive metal cluster materials… read more. TECHNICAL ARTICLE
Researchers develop novel ‘super-tetragonal’ sacrificial layer for freestanding oxide membranes
Phys.org March 18, 2024 Freestanding oxide membranes have a variety of interesting applications, but pulling these materials off the substrate after synthesis can be challenging. An international team of researchers (China, Austria) has developed a water-soluble sacrificial layer, “super-tetragonal” Sr4Al2O7 (SAOT). The low-symmetric crystal structure enabled a superior capability to sustain epitaxial strain, allowing for broad tunability in lattice constants resulting in structural coherency and defect-free interface in perovskite ABO3/SAOT heterostructures effectively restraining crack formation during the water release of freestanding oxide membranes. For a variety of nonferroelectric oxide membranes, the crack-free areas can span up to a millimeter in […]
Researchers discover new yttrium-hydrogen compounds with implications for high-pressure superconductivity
Phys.org March 14, 2024 An international team of researchers (Germany, UK, USA – University of Chicago) used synchrotron single-crystal x-ray diffraction (SCXRD) and found (two YH3 phases) and five previously unknown yttrium hydrides. These were synthesized in diamond anvil cells by laser heating yttrium with hydrogen-rich precursors—ammonia borane or paraffin oil. The arrangements of yttrium atoms in the crystal structures of new phases were determined based on SCXRD, and the hydrogen content estimations based on empirical relations and ab initio calculations revealed the following compounds: Y3H11, Y2H9, Y4H23, Y13H75, and Y4H25. They also uncovered a carbide and two yttrium allotropes. […]
Researchers prove fundamental limits of electromagnetic energy absorption
Phys.org March 14, 2024 Past work has considered the analytic properties of the reflection coefficient for a metal-backed slab and established a fundamental relationship for the minimal layer thickness to bandwidth ratio achievable for an absorber, but a similar relationship for non-metal-backed layers is not established. Based on Kramers–Kronig relations researchers at Duke University have developed a universal result. They validated their theory with transfer matrix calculations of homogeneous materials, and full-wave numerical simulations of electromagnetic metamaterials. According to the researchers their results place more general fundamental limits on absorbers, and it will be important for both fundamental and applied […]
Supercomputer simulations of super-diamond suggest a path to its creation
Phys.org March 18, 2024 Despite several experimental attempts, synthesis, and recovery of the theoretically predicted post-diamond BC8 phase remains elusive. Through quantum-accurate multimillion atom molecular dynamics (MD) simulations, an international team of researchers (USA – University of South Florida, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Sweden) uncovered the extreme metastability of diamond at very high pressures, significantly exceeding its range of thermodynamic stability. They predicted the post-diamond BC8 phase to be experimentally accessible only within a narrow high pressure–temperature region of the carbon phase diagram. The diamond to BC8 transformation proceeded through premelting followed by BC8 nucleation and […]
Top 10 Science and Technology Inventions for the Week of March 15, 2024
01. Researchers achieve quantum key distribution for cybersecurity in novel experiment 02. Materials research explores design rules and synthesis of quantum memory candidates 03. New research on tungsten unlocks potential for improving fusion materials 04. New type of tunable filter reveals the potential for terahertz wireless communications 05. Powerless mechanoluminescent touchscreen underwater 06. Preventing magnet meltdowns before they can start 07. Researchers generate super-fast electrons with table-top laser systems 08. Paper AI sensor mimics brain for health monitoring 09. Novel method improves Fourier transform infrared spectroscopy detection of ultra-low concentration trace substances 10. China promises more money for science in […]
A 3D view into chaos: Researchers visualize temperature-driven turbulence in liquid metal for the first time
Phys.org March 11, 2024 Researchers in Germany conducted an experiment inside a cylinder filled with the ternary alloy GaInSn focusing on the manifestation and dynamics of the large-scale circulation (LSC) in turbulent liquid metal convection. The large-scale flow structures were classified and characterized at Rayleigh numbers by means enabling the full reconstruction of the three-dimensional flow structures in the entire convection cell. They identified the dominating modes of the turbulent convection. The analysis revealed that a single-roll structure of the LSC alternates in short succession with double-roll structures or a three-roll structure. This was accompanied by dramatic fluctuations of the […]