Physics World June 18, 2018 An international team of researchers (Germany, Japan, Sweden, South Korea) has discovered a variety of new colour centres in lateral p-i-n diodes made from a polytype (a crystal structure) of silicon carbide called 4H-SiC that contains naturally occurring divacancies. The newly-discovered centres emit non-classical light in the visible and near-infrared range. One type of defect can even be excited using electrical means. This means that it might be integrated into compact electronics devices as there would be no need for an additional bulky laser system to optically excite it. The work opens new directions both […]
Tag Archives: Materials science
Light-bending nano-patterns for LEDs
Nanowerk June 8, 2018 Researchers in Singapore designed and experimentally realized high efficiency beam deflecting and polarization beam splitting metasurfaces consisting of GaN nanostructures etched on the GaN epitaxial substrate itself. They demonstrated a polarization insensitive beam deflecting metasurface with 64% and 90% absolute and relative efficiencies, and the broad functionality that can be realized on this platform. The broadband response in the blue wavelength range of 430–470 nm. The nanophotonic platform of GaN shows the way to off- and on-chip nonlinear and quantum photonic devices working efficiently at blue emission wavelengths common to many atomic quantum emitters such as Ca+ […]
Researchers achieve almost instant magnetization of matter by light
Phys.org May 28, 2018 The magnetization of a material is associated with the spatial ordering of the spins of its constituent particles. An international team of researchers (Brazil, Austria) demonstrated that light resonant with the band gap forces the antiferromagnetic semiconductor EuSe to enter ferromagnetic alignment in the picosecond timescale. By increasing the light intensity, the whole of the illuminated region can be fully magnetized… read more. TECHNICAL ARTICLE
An elastic fiber filled with electrodes set to revolutionize smart clothes
Science Daily May 25, 2018 Using thermal drawing researchers in Switzerland created hundreds‐of‐meters long multimaterial optical and electronic fibers and devices that can sustain up to 500% elastic deformation before recovering their initial shape. The fibers can detect even the slightest pressure and strain that makes them perfect for applications in smart clothing and prostheses, and for creating artificial nerves for robots… read more. TECHNICAL ARTICLE
Scientists discover new magnetic element
Phys.org May 24, s018 A team of researchers in the US (University of Minnesota, University of Wisconsin, industry) has demonstrated single element ferromagnetism in ruthenium. They observed a saturation magnetization of 148 and 160 emu cm−3 at room temperature and 10 K, respectively. Increasing thickness results in strain relaxation, and thus diluting the magnetization. Anomalous Hall measurements are used to confirm its ferromagnetic behavior. The discovery could be used to improve sensors, devices in the computer memory and logic industry, or other devices using magnetic materials… read more. Open Access TECHNICAL ARTICLE
The apparent inner calm of quantum materials
Nanowerk May 7, 2018 It was predicted that a set of topological excitations in a quantum material is likely to induce a phase transition. An international team of researchers (France, Switzerland, Sweden, Germany, Japan) has provided experimental confirmation of this theory in BACOVO (BaCo2V2O8). They found a novel topological phase transition in BACOVO, governed not by a single type of topological excitation, but by two different ones. In addition, they were able to choose which of the two sets would dominate the other. These results open a whole range of possibilities in quantum physics research… read more. Open Access TECHNICAL […]
Making new layered superconductors using high entropy alloys
Science Daily May 4, 2018 Use of layered materials with a molecular structure consisting of alternating superconducting layers and “blocking layers” acting as insulating spacers is used to design new superconductors that retain superconducting properties at higher temperatures. Researchers in Japan have created new superconductors made of layers of bismuth sulfide and a high entropy rare earth alloy oxyfluoride, containing five rare earth elements – lanthanum, cerium, praseodymium, neodymium, and samarium – at the same crystallographic site. The new material retains superconducting properties over a wider range of lattice parameters than materials without high-entropy-alloy states. The work promises a new […]
Motorizing fibres with geometric zero-energy modes
Phys.org May 4, 2018 An international team of researchers (France, Switzerland, Germany) used responsive materials to generate structures with built-in complex geometries, linear actuators and microswimmers. The results suggest that complex, fully functional machines composed solely from shape-changing materials might be possible. They show that prestrained polymer fibres closed into rings exhibit self-actuation and continuous motion when placed between two heat baths due to elastic deformations that arise from rotational-symmetry breaking around the rod’s axis. Their findings illustrate a simple but robust model to create active motion in mechanically prestrained objects… read more. TECHNICAL ARTICLE
A surprising new superconductor
Science Daily May 1, 2018 A team of researchers in the US (NIST, University of Colorado, University of Nevada Las Vegas, Argonne National Laboratory, Syracuse University) has shown that electroplated rhenium (Re) films in multilayers with metals such as Cu, Au, and Pd have an enhanced superconducting critical temperature relative to previous methods of preparing Re. The dc resistance and magnetic susceptibility indicate a critical temperature of approximately 6 K. It meets ideal characteristics desired for use in circuit boards for ultrafast, next-generation computing applications: superconducting at higher, easier-to-achieve critical temperatures, easy to work with mechanically, non-toxic, and melts at high […]
New carbon-dioxide-adsorbing crystals could form the basis of future biomedical materials that rely on the shape-memory effect
Science Daily April 27, 2018 The shape-memory effect in crystalline porous materials is poorly understood. An international team of researchers (Ireland, Japan, University of Southern Florida) reports the porous coordination network that exhibits a sorbate-induced shape-memory effect in which multiple sorbates, N2, CO2 and CO promote the effect. It exhibits three distinct phases: the as-synthesized α phase; a denser-activated β phase; and a shape-memory γ phase. Analysis of the structural information of the three phases helped them to understand structure-function relationships and propose crystal engineering principles for the design of more examples of shape-memory porous materials… read more. Open Access […]