Phys. org July 18, 2022 Researchers in Germany showed that precisely applied mechanical pressure can improve the electronic properties of a widely used ferroelectric semi-crystalline polymer material polyvinylidene fluoride (PVDF). However, PVDF’s structure, unlike crystals, is not completely ordered. They discovered that atomic force microscopy can be used to establish a certain electric order in the material. They scanned the material sample with a tip only a few nanometers in size. Using a laser they measured, evaluated the vibrations that were produced, and analyzed the material’s surface structure at the nano level. They discovered that this also changed the electrical […]
Key material development for fusion energy application
Phys.org July 22, 2022 In a review paper a team of researchers in China has introduced the latest development and strategy on fusion energy in China and reviewed the progresses of reduced activation ferritic/martensitic (RAFM) steel for engineering applications. It is considered to be the primary candidate structural material for blankets of ITER, CFETR and DEMO. Several RAFMs have been developed in China (CN-RAFMs) such as CLAM, CLF-1, modified RAFMs and oxide dispersion strengthened RAFMs (ODS-RAFMs). The mechanical properties, irradiation behaviors, additive manufacturing and joining technologies of structural materials have been comprehensively studied. Qualifications of CN-RAFMs are on-going for ITER-TBM […]
Photovoltaics: Fully scalable all-perovskite tandem solar modules
Science Daily July 14, 2022 Researchers in Germany have developed a prototype for fully scalable all-perovskite tandem solar modules which have an efficiency of up to 19.1 percent with an aperture area of 12.25 square centimeters. The improved efficiency was realized with optimized light paths, high-throughput laser scribing, and the use of established industrial coating methods. Perovskite solar cells with a tunable band gap are ideal tandem partners for solar cells made of other materials and for all-perovskite tandem solar cells. They were able to scale up individual perovskite cells with an efficiency of up to 23.5 percent .They feature […]
Physicists harness quantum ‘time reversal’ to measure vibrating atoms
Phys.org July 14, 2022 Linear quantum measurements with independent particles are bounded by the standard quantum limit, which limits the precision achievable in estimating unknown phase parameters. The standard quantum limit can be overcome by entangling the particles, but the sensitivity is often limited by the final state readout, especially for complex entangled many-body states with non-Gaussian probability distributions. By implementing an effective time-reversal protocol in an optically engineered many-body spin Hamiltonian a team of researchers in the US (MIT, Harvard University) has demonstrated a quantum measurement with non-Gaussian states with performance beyond the limit of the readout scheme. This […]
A quantum wave in two crystals
Phys.org July 18, 2022 In a crystal, all atoms are connected to each other and have a fixed spatial relationship to each other—so you can minimize the influence of external disturbances on the neutron wave. But this monolithic design limits the possibilities. Alignment of two crystals to create a neutron interferometer did not reach the required accuracy. Scanning X-ray interferometers also consist of separate silicon crystals and are similarly sensitive. An international team of researchers (Austria, France, Italy) used the technology developed for the X-ray interferometer. The team succeeded in detecting neutron interference in a system of two separate crystals. […]
Researchers create order from quantum chaos
Phys.org July 19, 2022 A team of researchers in the US (National Energy Research Laboratory, University of Colorado, University of Kentucky) selected a tetracenethiophene compound called TES TIPS-TT, which has a crystal structure in which all molecules share a common axis. Using time-resolved paramagnetic resonance spectroscopy they characterized the spin state of the electrons in the material. The observed spin sublevel populations are consistent with predictions from the JDE model, including preferential 5TT0 formation at z ‖ B0, with one caveat—two 5TT spin sublevels have little to no population. This may be due to crossings between the 5TT and 3TT […]
Researchers explore a hydrodynamic semiconductor where electrons flow like water
Phys.org July 20, 2022 An international team of researchers (USA – Columbia University, Cornell University, Brown University, Singapore, Japan) combined theoretical and experimental study of ambipolar hydrodynamic transport in bilayer graphene to demonstrate that the conductivity is given by the sum of two Drude-like terms that describe relative motion between electrons and holes, and the collective motion of the electron-hole plasma. As predicted, the measured conductivity of gapless, charge-neutral bilayer graphene was sample- and temperature-independent over a wide range. Away from neutrality, the electron-hole conductivity collapsed to a single curve, and a set of just four fitting parameters provided quantitative […]
Researchers present anti-reflective coating that blocks waves of many types
Phys.org July 14, 2022 An international team of researchers (Austria, France) has developed a method that allows the calculation of a tailor-made anti-reflective structure which can be used to design an additional layer to the medium only partially permeable to a wireless signal so that the entire signal can be channeled through the medium without reflections. To determine the anti-reflective structure they sent the waves through the medium and measured exactly in which way these waves are reflected by the material. Using a mathematical technique they calculated the corresponding compensating structure so that the combination of both media allowed the […]
Study shows that skyrmions and antiskyrmions can coexist at different temperatures
Phys.org July 21, 2022 A fundamental property of particles and antiparticles is their ability to annihilate one another. A similar behaviour is predicted for magnetic solitons1—localized spin textures that can be distinguished by their topological index Q. Theoretically, magnetic topological solitons with opposite values of Q, such as skyrmions and antiskyrmions, are expected to be able to continuously merge and annihilate. An international team of researchers (Germany, Sweden) demonstrated the creation and annihilation of skyrmion–antiskyrmion pairs in an exceptionally thin film of the cubic chiral magnet of B20-type FeGe. According to the researchers their observations are highly reproducible and are […]
Robots learn household tasks by watching humans
Phys.org July 22, 2022 Researchers at Carnegie Mellon University have developed a new learning method for robots called WHIRL, short for In-the-Wild Human Imitating Robot Learning. WHIRL is an efficient algorithm for one-shot visual imitation. It can learn directly from human-interaction videos and generalize that information to new tasks, making robots well-suited to learning household chores. With WHIRL, a robot can observe those tasks and gather the video data it needs to eventually determine how to complete the job itself. The robot watched as a researcher opened the refrigerator door. It recorded his movements, the swing of the door, the […]