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 […]

Materials research explores design rules and synthesis of quantum memory candidates

Phys.org   March 11, 2024 Stoichiometric Eu3+ compounds have recently shown promise for building dense, optically addressable quantum memory as the cations’ long nuclear spin coherence times and shielded 4f electron optical transitions provide reliable memory platforms but finding rare linewidth behavior within a wide range of potential chemical spaces remains difficult. Researchers at the University of Illinois, Urbana─Champaign, have found density functional theory (DFT) procedures that reliably reproduce known phase diagrams and correctly predict two experimentally realized quantum memory candidates. They synthesized the double perovskite halide Cs2NaEuF6 which is an air-stable compound with a calculated band gap of 5.0 eV […]

Research team develops a more durable coating against ice

Phys.org  February 27, 2024 An international team of researchers (Austria, Italy) deposited gradient polymers in one step via initiated chemical vapor deposition as an effective coating to mitigate ice accretion and reduce ice adhesion. The gradient structures easily overcame adhesion, stability, and durability issues of traditional fluorinated coatings. The coatings showed promising ice phobic performance by reducing ice adhesion, depressing the freezing point, delaying drop freezing, and inhibiting ice nucleation and frost propagation. They confirmed that lipophobicity correlated with surface energy discontinuities at the surface plane resulting from the random orientation of the fluorinated groups of PFDA. It could be […]

Researchers create new compound to build space-age antennas

Science Daily  February 29, 2024 Additive manufacturing with high-performance polymers can realize lightweight and complex geometries that can also be manufactured on board. However, polymers are electromagnetically inefficient for applications requiring electrical conductivity, such as guiding microwave signals. An international team of researchers (Canada, USA – Drexel University) developed MXene coated high-efficiency, lightweight additively manufactured microwave components with waveguiding functionality from 8 to 33 GHz, covering low earth orbit (LEO) frequencies, with a power-handling capability up to 10 dB and a transmission coefficient of 93 %. After a single dip-coating cycle, the polymer waveguide performed only 2 % below an […]

Novel nanocrystal harnesses full solar spectrum for hydrogen production

Nanowerk  February 27, 2024 Near infrared energy remains untapped toward the maneuvering of entire solar spectrum harvesting for fulfilling the nuts and bolts of solar hydrogen production. An international team of researchers (Taiwan, Japan)used Au@Cu7S4 yolk@shell nanocrystals as dual-plasmonic photocatalysts to achieve remarkable hydrogen production under visible and near infrared illumination. Data revealed the prevalence of long-lived charge separation states for Au@Cu7S4 under both visible and near infrared excitation. Combined with the advantageous features of yolk@shell nanostructures, Au@Cu7S4 achieved a peak quantum yield of 9.4%. The design of a sustainable visible- and near infrared-responsive photocatalytic system is expected to inspire […]

Physicists detect elusive ‘Bragg glass’ phase with machine learning tool

Phys.org  February 9, 2024 Detecting the Bragg glass phase has been challenging despite its sharp theoretical definition in terms of diverging correlation lengths. A team of researchers in the US (Cornell University, Stanford University, National Accelerator Laboratory, Argonne National Laboratory provided bulk probe evidence supporting a Bragg glass phase in the systematically disordered charge-density-wave material of PdxErTe3. They established a diverging correlation length in samples with moderate intercalation over a wide temperature range. According to the researchers their work advances our understanding of the complex interplay between disorder and fluctuation and the use of their analysis technique to target fluctuations […]

Strange New Kind of Magnetism Found Lurking In Material Just Six Atoms Thick

Science Alert  February 4, 2024 The existence of alternate mechanisms for magnetism that could naturally facilitate electrical control has been discussed theoretically but an experimental demonstration has not been done. An international team of researchers (Switzerland, Spain, US -University of Tennessee, Japan) investigated MoSe2/WS2 van der Waals heterostructures in the vicinity of Mott insulator states of electrons forming a frustrated triangular lattice and observed direct evidence of magnetic correlations originating from a kinetic mechanism. By directly measuring electronic magnetization they found that when the Mott state was electron-doped, the system exhibited ferromagnetic correlations in agreement with the Nagaoka mechanism… read […]

Physicists develop highly robust time crystal

Phys.org  February 1, 2024 Crystals spontaneously break the continuous translation symmetry of free space. An international team of researchers (Germany, Russia) demonstrated a robust continuous time crystal in an electron–nuclear spin system of a semiconductor tailored by tuning the material composition. Continuous, time-independent external driving of the sample produced periodic auto-oscillations with a coherence time exceeding hours. Varying the experimental parameters revealed wide ranges in which the time crystal remained stable. At the edges of these ranges, they found chaotic behaviour with a lifted periodicity corresponding to the melting of the crystal. According to the researchers time crystal state enabled […]

Researchers add a ‘twist’ to classical material design

Phys.org  January 24, 2024 Epitaxial growth of a crystalline film normally proceeds from one substrate. Researchers at Stanford University expanded the concept of epitaxy to a regime of “twisted epitaxy” with the epilayer crystal orientation between two substrates influenced by their relative orientation. They annealed nanometer-thick gold nanoparticles between two substrates of exfoliated hexagonal molybdenum disulfide with varying orientation of their basal planes with a mutual twist angle ranging from 0° to 60°. For larger twist angles, Au had only a small misorientation with the bottom MoS2. Further revealed a periodic strain variation (<|±0.5%|) in the Au nanodisks associated with […]

New conductive, cotton-based fiber developed for smart textiles

Science Daily  December 11, 2023 Blending conductive fillers with cellulose is the most common means of fiber production. Incorporating a high content of conductive fillers is necessary to achieve desirable conductivity. However, a high filler load deteriorates the processability and mechanical properties of the fibers. Researchers at Washington State University developed wet-spun cellulose-based fibers with a unique side-by-side (SBS) structure via sustainable processing. They engineered sustainable sources (cotton linter and post-consumer cotton waste) and a biocompatible intrinsically conductive polymer (i.e., polyaniline, PANI) into fibers containing two co-continuous phases arranged side-by-side… read more. TECHNICAL ARTICLE