Phys.org September 16, 2020 A one-dimensional topological superconductor with Majorana states bound to its ends can be realized by coupling a semiconductor nanowire to a superconductor in the presence of a strong magnetic field. However, the applied magnetic fields are detrimental to superconductivity, and constrain device layout, components, materials, fabrication, and operation. Using a ferromagnetic insulator instead of an applied field was theoretically proposed. Researchers in Denmark report transport measurements in hybrid nanowires using epitaxial layers of superconducting Al and the ferromagnetic insulator EuS on semiconducting InAs nanowires. They infer a remanent effective Zeeman field exceeding 1 T and observe stable […]
Tag Archives: Advanced materials
Mineral undergoes self-healing of irradiation damage
Phys.org September 9, 2020 Monazite–(Ce) is a common accessory rock component that bears petrogenetic information, which is widely used in geochronology and thermochronology, and is considered a potential host material for immobilization of radioactive waste. An international team of researchers (Austria, Germany, Russia, Czech Republic) conducted an ion-irradiation study that has unraveled the causes of the self-healing of monazite. They found that only in radiation-damaged monazite–(Ce), 4He ions cause gradual structural restoration. In contrast, its high-temperature annealed analogue and synthetic CePO4 experience He-irradiation damage. Alpha-assisted annealing contributes to preventing irradiation-induced amorphization of monazite–(Ce); however, this process is only significant above […]
Molecule to store solar energy developed
Science Daily August 31, 2020 An international team of researchers (Sweden, Hungary, India) has developed a molecule belonging to the molecular photoswitches group that can take on two different forms: a parent form that can absorb energy from sunlight, and an alternative form where the structure of the parent form is changed to become much more energy-rich, while remaining stable. Through calculations they show that the molecule would undergo the desired change within 200 femtoseconds. The concept of switching between aromatic and non-aromatic states of a molecule has a major potential in the field of molecular photoswitches. A possible long-term […]
Faster, more efficient energy storage could stem from holistic study of layered materials
Science Daily August 25, 2020 An international team of researchers (USA – Oak Ridge National Laboratory, Georgia State University, Tulane University, Drexel University, Portugal) integrated theoretical data from computational modeling of experimental data to pinpoint potential locations of a variety of charged ions in titanium carbide, the most studied MXene phase. MXenes are a class of two-dimensional materials constructed in layers that are only a few atoms thick. They were able to form links between theory and different types of materials characterization, ranging from very simple to very complex over a wide range of length and time scales. The study’s […]
Storing information in antiferromagnetic materials
EurekAlert August 24, 2020 An international team of researchers (Germany, France, Japan, Czech Republic) has shown that information storage in antiferromagnetic materials is fundamentally possible, and how efficiently information can be written electrically in insulating antiferromagnetic materials. For their measurements, the researchers used the antiferromagnetic insulator Cobalt oxide CoO – a model material that paves the way for applications. The result: Currents are much more efficient than magnetic fields to manipulate antiferromagnetic materials. This discovery opens the way toward applications ranging from smart cards that cannot be erased by external magnetic fields to ultrafast computers – thanks to the superior […]
Black silicon photodetector breaks the 100% efficiency limit
Phys.org August 14, 2020 Ultraviolet sensors are utilized in numerous fields although their performance is surprisingly poor. An international team of researchers (Finland, Spain, Germany) used a nanostructured silicon photodiode with self-induced junction to demonstrate that it is possible to make a device with a certified external quantum efficiency above 130% in UV range without external amplification. They showed that the high efficiency is based on effective utilization of multiple carrier generation by impact ionization taking place in the nanostructures. While the results can readily have a significant impact on the UV-sensor industry, the underlying technological concept can be applied […]
Insect wings inspire new ways to fight superbugs
EurekAlert August 18, 2020 New anti-bacterial surfaces are being developed, featuring different nanopatterns that mimic the deadly action of cicadas and dragonflies’ wings. In a review article an international team of researchers (Australia, Spain, USA – Ohio State University, UK) has detailed exactly how these patterns destroy bacteria – stretching, slicing, or tearing them apart. They point out that different species have wings that are better at killing some bacteria than others, the wing surfaces have different density, height, and diameter of the nanopillars. The nanostructured surfaces could be used in medical or industrial applications…read more. TECHNICAL ARTICLE
Physicists find misaligned carbon sheets yield unparalleled properties
Science Daily July 31, 2020 In an earlier study an international team of researchers (Yale University, UT Dallas, Japan) showed that when offset by 0.93 degrees, twisted bilayer graphene exhibits both superconducting and insulating states, thereby widening the magic angle significantly. In the current research they set out to determine how mid-infrared light might affect the conductance of electrons in twisted bilayer graphene. Their work involved calculating the light absorption based on the moiré pattern’s band structure. They showed that the theoretical results not only matched well with the experimental findings, but also pointed to a mechanism that is fundamentally […]
Researchers create surface coating that can create false infrared images
UC Berkeley July 23, 2020 At certain temperature tungsten-doped vanadium dioxide can phase shift from an insulator to a metal. An international team of researchers (US Berkeley, Singapore, China) created special structures made from delicately engineered thin films of tungsten-doped vanadium dioxide. With judicious engineering of the doping profile, the insulator-metal phase transition can even out, allowing the substance to emit a constant level of thermal radiation over wide range of temperature variations (15-70 degrees Celsius). This state of equilibrium prevents a camera from detecting the true infrared signals that an object normally emits around room temperature. The coatings can […]
Nature provides inspiration for researchers developing selective membranes
Nanowerk July 23, 2020 According to a team of researchers in the US (Yale University, Lawrence Livermore National Laboratory, UC Merced) in the future membranes may be engineered with the ability to select which substances they allow through, even to the point of distinguishing between very similar ions such as potassium and sodium. They introduce the challenges of state-of-the-art membranes with subnanometre pores to achieve high selectivity between solutes, analyse experimental and theoretical literature to discuss the molecular-level mechanisms that contribute to energy barriers for solute transport through subnanometre pores. They conclude by providing principles and guidelines for designing next-generation […]