Phys.org October 30, 2024 The rare earth RMn6Sn6 (R = rare earth) family magnetic kagome systems, where their kagome flat bands are calculated to be near the Fermi level in the paramagnetic phase have been reported. While partially filling a kagome flat band is predicted to give rise to a Stoner-type ferromagnetism, experimental visualization of the magnetic splitting across the ordering temperature has not been reported for any of these systems leaving the nature of magnetism in kagome magnets an open question. An international team of researchers (USA – Rice University, Brookhaven National Lab, Los Alamos National Laboratory, Israel, Czech Republic) probed […]
Category Archives: Materials science
New machine learning model quickly and accurately predicts dielectric function
Phys.org October 25, 2024 Fast and accurate prediction of dielectric function facilitates the development of novel dielectric materials, an ingredient of many cutting-edge technologies such as 6G networks. Researchers in Japan introduced a versatile machine-learning scheme implemented in Git hub for predicting dipole moments of molecular liquids to study dielectric properties. They attributed the center of mass of Wannier functions (called Wannier centers), to each chemical bond and created neural network models. They applied liquid methanol and ethanol to demonstrate that their neural network models successfully predicted the dipole moment of various liquid configurations in close agreement with DFT calculations. […]
Specially designed transistors allow researchers to ‘hear’ defects in a promising nanomaterial
Phys.org October 22, 2024 Single-crystal hexagonal boron nitride (hBN) is used extensively in many two-dimensional electronic and quantum devices, where defects significantly impact performance. An international team of researchers (Norway, Germany) examined the capture and emission dynamics of defects in hBN by utilizing low-frequency noise (LFN) spectroscopy in hBN-encapsulated and graphene-contacted MoS2 field-effect transistors (FETs). The low disorder of this heterostructure allowed the detection of random telegraph signals (RTS) in large device dimensions of 100 μm2 at cryogenic temperatures. Analysis of gate bias- and temperature-dependent LFN data indicated that RTS originated from a single trap species within hBN. Through calculations […]
Amorphous nanosheets created using hard-to-synthesize metal oxides and oxyhydroxides
Phys.org October 21, 2024 Amorphous 2D nanosheets have unique properties that are distinct from crystalline 2D nanosheets. However, compared with the vast library of crystalline 2D nanosheets, amorphous 2D nanosheets lack an efficient synthetic approach. Researchers in Japan developed a strategy that yields a library of 10 distinct amorphous 2D metal oxides/oxyhydroxides using solid-state surfactant crystals. A key feature of this process was a stepwise reaction using solid surfactant. The solid-state surfactant crystals have metal ions arranged in the interlayer space, and hydrolysis of the metal ions leads to the formation of isolated clusters in the surfactant crystals via limited […]
The corners where atoms meet may provide a path to new materials for extreme conditions
Phys.org October 16, 2024 A team of researchers in the US (George Washington University, George Mason University, Lawrence Berkeley University, Johns Hopkinson University, Sandia National Laboratory, Leigh University) presented large-scale atomistic simulations that revealed triple junction (TJ) segregation in Pt–Au nanocrystalline alloys in agreement with experimental observations. While existing studies suggested grain boundary solute segregation as a route to thermally stabilize nanocrystalline materials with respect to grain coarsening, the researchers quantitatively showed that it was specifically the segregation to TJs that dominated the observed stability of the alloys. The results showed that doping the TJs made them immobile, thereby locking […]
Engineering perovskite materials at the atomic level paves way for new lasers, LEDs
Phys.org October 11, 2024 Layered hybrid perovskites (LHPs) have emerged as promising reduced-dimensional semiconductors for next-generation photonic and energy applications where controlling the size, orientation, and distribution of quantum wells (QWs) is of paramount importance. A team of researchers in the US (North Carolina State University, Brookhaven National Laboratory) revealed that bulky molecular spacers act as crystal-terminating ligands to form colloidal nanoplatelets (NPLs) during early stages of LHP formation. They proved that NPLs ripen and grow, playing a decisive role in the time evolution of QW size, population distribution, and orientation. They demonstrated that antisolvent drip interrupts NPL ripening and […]
Scientists use light to visualize magnetic domains in quantum materials
Phys.org October 11, 2024 Researchers in Japan visualized antiferromagnetic domains in a representative quasi-one-dimensional antiferromagnet using nonreciprocal directional dichroism, which differentiated the optical absorption of a pair of antiferromagnetic domains. Opposite antiferromagnetic domains, each about submillimeter in size, were found to coexist in a single-crystal specimen, and the domain walls ran predominantly along the spin chains. They showed that the domain walls could be moved by an applied electric field through a magnetoelectric coupling, and the direction of the domain walls was maintained during the motion. They explained the domain wall anisotropy by the quasi-one-dimensional nature of the exchange interactions. […]
New materials and techniques show promise for microelectronics and quantum technologies
Phys.org October 2, 2024 Low dimensional (LD) organic metal halide hybrids (OMHHs) have recently emerged as new generation functional materials with exceptional structural and property tunability. Despite the remarkable advances in the development of LD OMHHs, optical properties have been the major functionality extensively investigated for most of LD OMHHs developed to date, while other properties such as magnetic and electronic properties, remain significantly under-explored. An international team of researchers (USA – Florida State University, North Carolina State University, UCLA, Israel) describe the characterization of the magnetic and electronic properties of a 1D OMHH, organic-copper (II) chloride hybrid (C8H22N2)Cu2Cl6. Due […]
Theoretical physicist uncovers how twisting layers of a material can generate a mysterious electron-path-deflecting effect
Phys.org October 4, 2024 Studies of moiré systems have explained the effect of superlattice modulations on their properties, demonstrating new correlated phases. However, most experimental studies have focused on a few layers in two-dimensional systems. Extending twistronics to three dimensions, in which the twist extends into the third dimension, remains underexplored because of the challenges associated with the manual stacking of layers. A team of researchers in the US (University of Pennsylvania, SLAC National Accelerator Laboratory, University of Wisconsin-Madison) studied three-dimensional twistronics using a self-assembled twisted spiral superlattice of multilayered WS2. Their findings showed an opto-twistronic Hall effect driven by […]
Engineers 3D print sturdy glass bricks for building structures
MIT News September 24, 2024 There is minimal research on the additive manufacturing (AM) viability to produce structural building components, which could reduce tooling costs and increase flexibility for their production. A team of researchers in the US (MIT, industry) has provided design, manufacturing, and experimental testing to assess the feasibility of using glass AM to produce interlocking masonry units for the construction industry. Their glass 3D printer could print a maximum volume for producing full-size masonry units. They discussed how to adapt design guidelines for glass AM to produce interlocking units, evaluated fabrication ease and structural performance using three […]