Phys.org July 14, 2020 Terahertz radiation potentially has applications in next-generation wireless communications (6G/7G), security systems, biomedicine, etc. because of the lack of appropriate materials and sophisticated optical components for flexible control of terahertz waves. Researchers in Japan have engineered a 2.28-µm ultra-thin terahertz metasurface collimator with a high directivity of 4.6 times consisting of 339 pairs of meta-atoms compared with a single terahertz continuous-wave source. The metasurface exhibits an extremely high refractive index of 15.0 and a low reflectance of 15.5% at 3.0 THz. It should facilitate ground-breaking applications such as arbitrary phase converters, solid immersion lenses, and cloaking…read more. […]
Tag Archives: S&T Japan
A path to new nanofluidic devices applying spintronics technology
Phys.org July 2, 2020 Hydrodynamic motion can generate a flux of electron-spin’s angular momentum via the coupling between fluid rotation and electron spins resulting in spin hydrodynamic generation (SHDG). Researchers in Japan have demonstrated electric voltage generation due to the SHDG in a laminar flow of a liquid-metal mercury. They experimentally confirmed that in the laminar flow region, energy conversion efficiency was increased by approximately 100,000 times. The technique has applications in spintronics-based nanofluidic devices such as liquid metal flow, cooling mechanisms in fast breeder reactors or semiconductor devices, as well as application to flowmeters that electrically measure micro-flows…read more. […]
A Metal-like Quantum Gas: A pathbreaking platform for quantum simulation
EurekAlert June 22, 2020 Electronic properties of condensed matter are often determined by an intricate competition between kinetic energy that aims to overlap and delocalize electronic wave functions across the crystal lattice, and localizing electron-electron interactions. In contrast, the gaseous phase is characterized by valence electrons tightly localized around the ionic atom cores in discrete quantum states with well-defined energies. A hybrid state of matter is created when a gas of isolated atoms is suddenly excited to a state where electronic wave functions spatially overlap like in a solid. Researchers in Japan created such a hybrid state with overlapping high-lying electronic […]
Terahertz radiation can disrupt proteins in living cells
EurekAlert June 2, 2020 Because terahertz radiation is stopped by liquids and is non-ionizing it is considered generally safe for use in the airports for scanning passengers. However, researchers in Japan have discovered that the energy from the light could enter into water as a “shockwave.” They investigated (G)-actin and (F)-actin, which have different structures and functions. Looking at the effect of terahertz radiation on the growth of chains in an aqueous solution of actin, they found that it led to a decrease in filaments, preventing the (G)-actin from forming chains and becoming (F)-actin. Ruling out the rise in temperature, […]
Untwisting plastics for charging Internet-of-things devices
Nanowerk May 27, 2020 To use body heat to charge some types of micro-devices and sensors requires lightweight, non-toxic, wearable, and flexible thermoelectric generators. Researchers in Japan studied the thermoelectric properties of a highly conductive thiophene-based polymer, called PBTTT. They found that doping the polymer with a thin ion electrolyte gel improves conductivity and infiltrates the polymer successfully when a specific electric voltage is applied. Doping it with a critical amount of electrolyte untwists the highly twisted chain and creates links between its crystalline parts, improving electron conductivity. They are now looking into ways to optimize the thermoelectric performance of […]
‘Tantalizing’ clues about why a mysterious material switches from conductor to insulator
Nanowerk May 18, 2020 Researchers in Japan created crystals of tantalum disulfide and then cleaved the crystals in a vacuum to reveal ultra-clean surfaces which they examined, at a temperature close to absolute zero. Using quantum tunneling they studied the degree of conducting behavior of the material. The results showed that there was indeed a stacking of layers which effectively arranged them into pairs. Sometimes the crystals cleaved between the pairs of layers, and sometimes through a pair, breaking it. They performed spectroscopy on both the paired and unpaired layers and found that even the unpaired ones are insulating, leaving […]
Room-temperature superionic conduction achieved using pseudorotation of hydride complexes
Phys.org May 13, 2020 Solid-state ionic conductors’ superior ionic conductivities require high temperature to activate the rotation of polyanions, which conversely means low conductivities at room temperature. Researchers in Japan were able to reduce the activation temperature by using transition metal hydride complexes as a new class of rotatable polyanions, wherein hydrogen is the sole ligand species, covalently binding to single transition metals. The rotation of transition metal hydride complexes only requires displacements of highly mobile hydrogen and can therefore be expected to occur with low activation energy. The mechanism is quite general and would be useful in lowering the […]
New ‘brick’ for nanotechnology: Graphene Nanomesh
EurekAlert April 20, 2020 Researchers in Japan have demonstrated that large area suspended graphene nanomesh is quickly achievable by the helium ion beam microscopy with sub-10 nm nanopore diameter and well-controlled pitches. Comparing to slow speed TEM patterning, the helium ion beam milling technique overcomes the speed limitation, and meanwhile, provides a high imaging resolution. With the initial electrical measurements, they found that the thermal activation energy of the graphene nanomesh increased exponentially by increasing the porosity of the graphene nanomesh. This immediately provides a new method for bandgap engineering beyond the conventional nanoribbon method. The research provides a practical […]
Unprecedented 3D images of live cells plus details of molecules inside
Nanowerk April 20, 2020 Label-free contrasts of Quantitative phase imaging (QPI) and molecular vibrational imaging (MVI) are inherently complementary and difficult to integrate due to their reliance on different light–matter interactions. Researchers in Japan present a unified imaging scheme with simultaneous and in situ acquisition of quantitative phase and molecular vibrational contrasts of single cells in the QPI framework using the mid-infrared photothermal effect. The research may enable new analyses, especially for studying complex and fragile biological phenomena such as drug delivery, cellular disease, and stem cell development…read more. Open Access TECHNICA L ARTICLE Concept of MV-QPI. (a) Principle of […]
Novel tin ‘bubbles’ spur advances in the development of integrated chips
EurekAlert April 15, 2020 Low density materials can control plasma properties of laser absorption, which can enhance quantum beam generation. Researchers in Japan propose a target source based on a hollow sub-millimeter microcapsule fabricated from polyelectrolyte cationic and anionic surfactant on air bubbles. The lightweight microcapsules acted as a scaffold for surface coating by tin (IV) oxide nanoparticles. In a proof of concept study the laser conversion efficiency at 13.5 nm 2% bandwidth from the tin-coated microcapsule (0.8%) was competitive compared with bulk tin (1%). According to the researchers microcapsule aggregates could be utilized as a potential small scale/compact EUV source […]