Nanowerk July 1, 2020 By connecting electromagnetic waves and magnetism to create a system made of magnon polaritons an international team of researchers (USA- Argonne National Laboratory, UK) has demonstrated the existence of an “exceptional surface”. Through experiments, they have shown that EPs form a three-dimensional exceptional surface (ES) when the system is tuned in a four-dimensional synthetic space. They found that an exceptional saddle point (ESP) exists in the ES which originates from the unique couplings between magnons and microwave photons. It exhibits unique anisotropic behaviors in both the real and imaginary parts of the eigenfrequencies. The findings open […]
Cartwheeling light reveals new optical phenomenon
Nanowerk June 29, 2020 While there are numerous forms of light polarization, only linear and circular polarizations, which have wave motion in a flat sheet or helix, respectively, are typically used. A team of researchers in the US (Rice University, UMass Dartmouth) utilized trochoidal polarizations with cartwheeling wave motion. They demonstrated that single gold nanorod dimers can discriminate between trochoidal fields rotating in opposite directions, which they named trochoidal dichroism. Trochoidal dichroism forms an additional classification of polarized light–matter interaction and could inspire the development of optical studies uniquely sensitive to molecules with cartwheeling charge motion, potentially relevant for probing […]
A completely new plasmonic chip for ultrafast data transmission using light
Techxplore.com July 3, 2020 To address the challenge of increasing data rates an international team of researchers (Switzerland, Germany, USA- University of Washington, Israel, Greece) has developed a monolithically integrated electro-optical transmitter that can achieve symbol rates beyond 100 GBd. They combined advanced bipolar CMOS with silicon plasmonics, and addressed key challenges in monolithic integration through co-design of the electronic and plasmonic layers, including thermal design, packaging, and a nonlinear organic electro-optic material. They demonstrated their technique by developing two modulator concepts—an ultra-compact plasmonic modulator and a silicon-plasmonic modulator with photonic routing—both directly processed onto the bipolar CMOS electronics. The findings […]
Computing collaboration reveals global ripple effect of shifting monsoons
Phys.org June 29, 2020 An international team of researchers (USA – Oak Ridge National Laboratory, UCLA, Mexico, Brazil, Italy, Hong Kong, Nigeria, Senegal, Rwanda, Pakistan) used an ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide an elaborate set of projections to date that illustrates possible futures for major monsoon regions. Each simulation covers the period from 1970 through 2100. They found that the weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. This causes […]
Exotic never before seen particle discovered at CERN
Phys.org July 1, 2020 Researchers at CERN led by UK scientists found the new tetraquark using the particle-hunting technique of looking for an excess of collision events called bumps, over a smooth background of events. The bump has a statistical significance of more than five standard deviations, the usual threshold for claiming the discovery of a new particle, and it corresponds to a mass at which particles composed of four charm quarks are predicted to exist. As with previous tetraquark discoveries, it is not completely clear whether the new particle is a “true tetraquark”, that is, a system of four […]
Extensive review of spin-gapless semiconductors: Next-generation spintronics candidates
EurekAlert June 26, 2020 The spin‐gapless semiconductors (SGSs) are a new class of zero‐gap materials which have fully spin polarized electrons and holes. They bridge the zero‐gap materials and the half‐metals. The band structures of the SGSs can have two types of energy dispersion: Dirac linear dispersion and parabolic dispersion. Researchers in Australia review both methods in different material systems and the concepts of the SGS, novel spin and charge states, and the potential applications of SGSs in next‐generation spintronic devices…read more. TECHNICAL ARTICLE
Light from inside the tunnel
Nanowerk June 30, 2020 In their experiment researchers in Germany focused two ultrashort light pulses with different wavelengths and slightly different propagation directions onto a thin slab of glass. A time- and frequency-resolved analysis of the emerging light emission showed that the current associated with the quantum mechanical tunneling process itself creates an optical non-linearity. The findings significantly expand both the fundamental understanding of optical non-linearity in dielectric materials and its potential for applications in information processing and light-based material processing…read more. TECHNICAL ARTICLE
The lightest shielding material in the world
EurekAlert July 2, 2020 An international team of researchers (Switzerland, Singapore) used nanofibers of cellulose as the basis for making an aerogel which is a light, highly porous material. Cellulose fibres obtained from wood enable a wide range of chemical modifications. The composite of cellulose nanofibers and silver nanowires created ultra-light fine structures which provide excellent shielding against electromagnetic radiation. The material has a density of 1.7 milligrams per cubic centimeter, achieves more than 40 dB shielding in the frequency range of high-resolution radar radiation (8 to 12 GHz) – in other words: virtually all radiation in this frequency range […]
Multifunctional nanofiber protects against explosions, extreme temps
Science Daily June 29, 2020 Current protection against both thermal and ballistic threats is a combination of multiple high-performance materials that increases equipment weight and complexity. Using para-aramid polymers as the building block researchers at Harvard University engineered precursor solutions to be fluid-like during fiber spinning and solid-like during fiber formation. This allowed for the fabrication of porous, continuous para-aramid fiber sheets (pAFS). Although exhibiting moderately reduced single-fiber mechanics, these pAFS had fragment projectile resistance comparable with commercial para-aramids, while providing 20-fold heat-insulation capability. With these synergistic properties, the nanofiber sheets act as a multifunctional material that can provide improved simultaneous protection…read more. Open […]
Nanoelectromechanical switches based reconfigurable computing
Nanowerk June 29, 2020 An international team of researchers (China, USA – University of Nebraska, UC Berkeley) has developed a simple NEM switch by exploiting a switchable nanocrack controlled by an electric field in a metallic alloy-ferroelectric heterostructure. The open and closed states of the crack are programmed under a cyclic electric field. The crack-based complementary nanoelectromechanical (CNEM) switches are leveraged to construct energy-efficient and high-density reconfigurable computing. The device integrates the advantages of ferroelectric and NEM switch, such as nonvolatility, a quasi-zero OFF-state leakage current and a low operating voltage. Complementary switching enables the device to operate as a […]