Science Daily November 2, 2021 single-molecule conductance falls off sharply with the length of the molecule so that only extremely short stretches of DNA are useful for electrical measurements. Researchers in Japan achieved an unconventionally high conductivity with a long DNA molecule-based junction in a “zipper” configuration that also shows a remarkable self-restoring ability under electrical failure. The team used a 10-mer and a 90-mer DNA strand to form a zipper-like structure and attached them to either a gold surface or to the metal tip of a scanning tunneling microscope. The separation between the tip and the surface constituted the […]
Towards straintronics: Guiding excitons in 2D materials
Science Daily October 30, 2021 Strain engineering is a powerful tool in designing artificial platforms for high-temperature excitonic quantum devices. An international team of researchers (USA – City College of New York, Germany, Japan) has created excitonic wires, essentially one-dimensional channels for excitons in what is otherwise a two-dimensional semiconductor by depositing the atomically thin 2D crystal on top of a microscopically small wire they created a small, elongated dent in the two-dimensional material, slightly pulling apart the atoms in the two-dimensional crystal and inducing strain in the material. For excitons, this dent is much like a pipe and once trapped […]
Trapping spins with sound
Science Daily November 1, 2021 Lattice defects in crystals often come along with certain magnetic properties. To use them as promising systems for applications in quantum technologies an international team of researchers (Germany, Russia) has developed an efficient method to control their spin states using surface acoustic waves (SAW). They demonstrated a giant interaction between the strain field of SAW and the excited-state spin of silicon vacancies in silicon carbide, which is about two orders of magnitude stronger than in the ground state. The simultaneous spin driving in the ground and excited states with the same SAW leads to the […]
Top 10 Science and Technology Inventions for the Week of October 29, 2021
01. Controlling light with a material three atoms thick 02. Electrical control over designer quantum materials 03. Engineers develop flexible, self-healing material to protect steel from the elements 04. Nature’s strongest glue now works in both wet and salty environments 05. New chiral nanostructures to extend the material platform 06. On-water creation of conducting MOF nanosheets 07. Researchers develop broadband spintronic-metasurface terahertz emitters with tunable chirality 08. Researchers discover new way to generate light through use of pre-existing defects in semiconductor materials 09. Shape-shifting materials with infinite possibilities 10. Stronger than spider silk: Bagworm silk enables strong conducting fibers And […]
Controlling light with a material three atoms thick
Phys.org October 22, 2021 An international team of researchers (USA – Caltech, Japan) constructed a material from black phosphorous which has anisotropic optical properties. As the black phosphorous is a semiconductor, structures built from black phosphorous can control the polarization of light as an electric signal is applied to them. This makes it possible to make an array of these elements each of which can convert the polarization into a different reflected polarization state. A telecommunications device based on thin layers of black phosphorous could tune the polarization of each signal so that they don’t interfere with each other. This […]
Electrical control over designer quantum materials
Science Daily October 22, 2021 Recently engineered stacks of two-dimensional materials have emerged as a powerful platform for studying quantum correlations between electronic states. However, the strength of the interaction between the quantum states is typically fixed once a stack is fabricated. An international team of researchers (Switzerland, Japan) demonstrated that they can induce Feshbach resonance in their system allowing to tune the interaction strength between quantum entities by bringing them into resonance with a bound state. In their case the bounds states were between an exciton in one layer and a hole in the other layer. It turns out […]
Fighting viruses with interchangeable defense genes
Science Daily October 21, 2021 Although it is generally accepted that phages drive bacterial evolution, how these dynamics play out in the wild remains poorly understood. An international team of researchers (USA – MIT, Vienna, France) found that susceptibility to viral killing in marine Vibrio is mediated by large and highly diverse mobile genetic elements. These phage defense elements display exceedingly fast evolutionary turnover, resulting in differential phage susceptibility among clonal bacterial strains while phage receptors remain invariant. Protection is cumulative, and a single bacterial genome can harbor 6 to 12 defense elements, accounting for more than 90% of the […]
Engineers develop flexible, self-healing material to protect steel from the elements
Phys.org October 22, 2021 An international team of researchers (USA – Rice University, South Dakota School of Mines and Technology, SUNY Buffalo, George Washington University, Rensselaer Polytechnic Institute, Canada) has designed a lightweight sulfur–selenium (S–Se) alloy with high stiffness and ductility that can serve as an excellent corrosion-resistant coating with protection efficiency of ≈99.9% for steel in a wide range of diverse environments. S–Se coated mild steel showed a corrosion rate that is 6–7 orders of magnitude lower than bare metal in abiotic (simulated seawater and sodium sulfate solution) and biotic (sulfate-reducing bacterial medium) environments. The coating is strongly adhesive, […]
Nature’s strongest glue now works in both wet and salty environments
Phys.org October 27, 2021 An aquatic bacterium called Caulobacter crescentus produces an extremely powerful glue called “holdfast,” which adheres to its surrounding wet surfaces, such as pipes and fresh water. To improve holdfast adhesion in high salinity environments researchers in Canada compared Caulobacter crescentus with a marine relative called Hirschia baltica. They found both had the same genes to synthesize holdfast indicating they used the same type of glue. Hirschia baltica holdfast also appeared to perform very well in a saline environment, which is its natural environment. By manipulating the level of expression of a particular gene whose function is […]
New chiral nanostructures to extend the material platform
Phys.org October 22, 2021 The majority of previously developed chiral nanomaterials reveal the optical activity in a relatively shorter wavelength range (ultraviolet–visible, UV–vis), not in short-wave infrared (SWIR). An international team of researchers (South Korea, USA – University of Michigan) has demonstrated a versatile method to synthesize chiral copper sulfides using cysteine, as the stabilizer, and transferring the chirality from molecular- to the microscale through self-assembly. The assembled structures showed broad chiroptical activity in the UV–vis-NIR-SWIR region (200–2500 nm). They could tune the chiroptical activity by simply changing the reaction conditions. This approach can be extended to materials platforms for […]