Nanowerk June 2, 2021 Researchers at Sandia National Laboratory have developed a heterogeneously integrated acoustoelectric material platform consisting of a 50 nm indium gallium arsenide epitaxial semiconductor film in direct contact with a 41° YX lithium niobate piezoelectric substrate. They demonstrated three of the main components of an all-acoustic radiofrequency signal processor: passive delay line filters, amplifiers, and circulators. Heterogeneous integration allows for simultaneous, independent optimization of the piezoelectric-acoustic and electronic properties, leading to the highest performing surface acoustic wave amplifiers in terms of gain per unit length and DC power dissipation. They described how the remaining components of an all-acoustic […]
Top 10 Science and Technology Inventions for the Week of May 28, 2021
01. Biologists construct a ‘periodic table’ for cell nuclei 02. New quantum material discovered 03. One material, two functionalities 04. Quantum electronics: ‘Bite’ defects in bottom-up graphene nanoribbons 05. Quantum sensing: Odd angles make for strong spin-spin coupling 06. Making the invisible visible 07. Slender robotic finger senses buried items 08. A new ‘gold standard’ compound for generating electricity from heat 09. Folding 2D materials gives them new properties useful for quantum communications 10. Understanding of invisible but mighty particles in Earth’s radiation belts And others… New climate predictions increase likelihood of temporarily reaching 1.5 °C in next 5 years […]
Biologists construct a ‘periodic table’ for cell nuclei
Phys.org May 27, 2021 An international team researchers from many countries investigated genome folding across the eukaryotic tree of life. They found two types of 3D genome architectures at the chromosome scale. Each type appears and disappears repeatedly during eukaryotic evolution. The type of genome architecture that an organism exhibits correlates with the absence of condensin II subunits. Moreover, condensin II depletion converts the architecture of the human genome to a state resembling that seen in organisms such as fungi or mosquitoes. In this state, centromeres cluster together at nucleoli, and heterochromatin domains merge. They propose a physical model in […]
Folding 2D materials gives them new properties useful for quantum communications
Nanowerk May 24, 2021 The use of 2D materials for nonlinear optics are limited by intrinsically small light-matter interaction length and (typically) flat-lying geometries. Researchers in the UK arranged 2D sheets of tungsten (WS2) in a new way to create a 3D arrangement they called a nanomesh. Its unique characteristics are the result of the specific synthesis process they developed. Only light with energy larger than the energy gap can interact with the material in a useful way. If new energy levels are introduced inside this energy gap, the doubling of frequency of the light that passes through the material […]
Making the invisible visible
Science Daily May 20, 2021 It has so far been difficult to gain a more accurate picture of the course of chemical reactions at the atomic level. An international team of researchers (Germany, USA – UC Berkeley, UC San Diego, SLAC National Accelerator Laboratory, France) has shown second harmonic generation on a table-top extreme ultraviolet source. To investigate the surface of titanium sample down to the atomic level they set up a special focusing geometry, consisting of an elliptically shaped mirror to concentrate the laser radiation onto a small area. They focused the radiation with a wavelength of 32.8 nanometres […]
New climate predictions increase likelihood of temporarily reaching 1.5 °C in next 5 years
World Meteorological Organization May 27, 2021 According to the Global Annual to Decadal Climate Update https://hadleyserver.metoffice.gov.uk/wmolc/ , produced by the United Kingdom’s Met Office, there is about a 40% chance of the annual average global temperature temporarily reaching 1.5°C above the pre-industrial level in at least one of the next five years – and these odds are increasing with time, according to a new climate update issued by the World Meteorological Organization (WMO). There is a 90% likelihood of at least one year between 2021-2025 becoming the warmest on record. This is mainly due to using an improved temperature dataset […]
A new ‘gold standard’ compound for generating electricity from heat
Phys.org May 26, 2021 The principal challenges in current thermoelectric power generation modules are the availability of stable, diffusion-resistant, lossless electrical and thermal metal–semiconductor contacts that do not degrade at the hot end nor cause reductions in device efficiency. Transverse thermoelectrics avoid this problem by producing a current that runs perpendicular to the conducting device, requiring contacts only on the cold end of the generator. However, the materials known to create this sideways voltage are impractically inefficient. A team of researchers in the US (Ohio State University, University of Illinois) demonstrated that a layered crystal consisting of the elements rhenium […]
New quantum material discovered
Nanowerk May 26, 2021 Usually, quantum critical behaviour is studied in metals or insulators. But an international team of researchers (USA – Johns Hopkins University, University of Maryland, NIST, Rice University, Austria) looked at a semimetal which is a compound of cerium, ruthenium, and tin – with properties that lie between those of metals and semiconductors. Usually, quantum criticality can only be created under specific environmental conditions however, this semimetal turned out to be quantum critical without any external influences at all. They suspect that it may be because it has a highly correlated electron system where the electrons interact […]
One material, two functionalities
Nanowerk May 25, 2021 Flexible metamaterials often harness zero-energy deformation modes. To date they have a single property, such as a single shape change, or are pluripotent. An international team of researchers (the Netherlands, Switzerland) has introduced a class of oligomodal metamaterials that encode a few distinct properties that can be selectively controlled under uniaxial compression. They demonstrated this concept by introducing a combinatorial design space containing various families of metamaterials. They included monomodal (with a single zero-energy deformation mode); oligomodal (with a constant number of zero-energy deformation modes); and plurimodal (with many zero-energy deformation modes), whose number increases with system […]
Quantum electronics: ‘Bite’ defects in bottom-up graphene nanoribbons
Science Daily May 25, 2021 Researchers in Switzerland have shown the nature of the structural disorder in bottom-up zigzag graphene nanoribbons along with its effect on the magnetism and electronic transport based on scanning probe microscopies and first-principles calculations. They found that edge-missing m-xylene units emerging during the cyclodehydrogenation step of the on-surface synthesis are the most common point defects. These “bite” defects act as spin-1 paramagnetic centers, severely disrupting the conductance spectrum around the band extrema, and give rise to spin-polarized charge transport. They also showed that the electronic conductance across graphene nanoribbons is more sensitive to “bite” defects […]