The magic angle of twisted graphene
2021-02-23
(Press-News.org) Graphene, a two-dimensional material composed exclusively of carbon, has revealed extraordinary properties, including thermal and electrical conductivity, transparency, and flexibility. When combined, these properties become particularly interesting in the age of touch screens and flexible electronics! 'Unlike 3D materials, graphene has a height reduced to the ultimate dimension of the atom. It's therefore a carbon atom plane,' explains Prof. Jean-Christophe Charlier, a specialist in nanoscopic physics at the Institute of Condensed Matter and Nanosciences of UCLouvain.
In a study published in Nature, the scientist and his team dissected the behaviour of electrons when two layers of graphene superimposed at an angle of 1.1 degrees (the so-called 'magic angle') produce a moiré effect. Well known to photographers, painters and fashion specialists, this optical effect consists of a figure composed of dark and light domains resulting from the superposition of two gratings. 'When two layers of graphene are superimposed with this magic angle, they give rise to superconductivity. They therefore conduct electricity without any resistance,' Prof. Charlier says. This property is more than useful for transporting electricity without loss of energy. 'We've shown that the two graphene planes twisted in this way interact and lead to a restructuring of the atoms into domains where electrons are trapped and localised in space.' However, by definition, electrons tend to move away from one other, repelled by their respective negative charges. 'To limit their interactions, the electrons can organise themselves by aligning their spin, which gives them magnetic properties, or by forming an insulator, or by pairing up to produce superconductivity.' It's the last that occurs in the case of bilayer graphene twisted at the magic angle. In addition, the scientists have shown that phonons, atom particles responsible for vibrations in solid materials, are also trapped in the domains formed by the twisted graphene.
The synthesis of new 2D materials and the observation of the extraordinary properties which can be derived from them have led to a twistronics craze driven by the idea of one day being able to create structures with the desired properties 'brick by brick', or to extrapolate knowledge acquired on simple materials, such as graphene, to more complex materials, allowing for better control or performance of superconducting systems in everyday life. Examples include the superconducting coils in Japanese magnetic levitation trains (Maglev), which levitate above the rails, or the superconducting magnet in magnetic resonance imaging (MRI) equipment.
INFORMATION:
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-02-23
Its muscular body shape and large pectoral fins are perfect for long-distance travel, yet movement patterns of the whitespotted eagle ray (Aetobatus narinari) remain a mystery. Researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute in collaboration with Mote Marine Laboratory & Aquarium, the University of Florida and the Florida Fish and Wildlife Conservation Commission, are the first to conduct a multiyear study examining large-scale movements of whitespotted eagle rays in United States waters.
Between 2016 and 2018, scientists fitted 54 rays with acoustic transmitters ...
2021-02-23
Doha, Qatar - (February 23, 2021) - A group of researchers at Qatar Foundation have reported the first and largest genetic association study in the Middle East, that has been published online in Nature Communications - a leading a peer-reviewed, open access, scientific journal published by Nature Research.
The study titled "Whole genome sequencing in the Middle Eastern Qatari population identifies genetic associations with 45 clinically relevant traits" highlights a vital piece of information wherein now there is a better understanding of the genetic risk factors that are specific to the Arab population, including those that are shared with other ethnicities.
Qatar was among the first countries to launch its own large-scale, national genome project. Qatar Genome ...
2021-02-23
A recent genetic study at the University of Helsinki provides new information on the occurrence of a DVL2 gene defect associated with a screw tail and its relevance to canine constitution and health. The variant was found in several Bulldog and Pit Bull type breeds, and it was shown to result in caudal vertebral anomalies and shortening of the muzzle. The DLV2 variant may also affect the development of the heart.
Dog breeding is often focused on appearance. In some breeds, the ideal body shape is bulky, with a broad head and short muzzle, short legs and a very short and kinked tail, also known as a "screw tail". In a previous study in the United States, screw tail was linked to a variant in the DVL2 gene. The variant has become enriched ...
2021-02-23
According to recent estimates, there will be roughly 10 billion people to feed in 2050. Agricultural production will need to increase by almost 56% to guarantee food security globally, without converting more land for agriculture (in line with environmental and climate targets). This unprecedented challenge has ushered in the era of "smart agriculture," which promises to revolutionize food production by combining agricultural techniques with information technology, automation, and artificial intelligence. This new era, called "Agriculture 4.0," could ensure sustainable food production for the entire world. However, as communities gradually embrace smart agriculture, it is important to understand how to manage the security and privacy risks associated with the integration of ...
2021-02-23
Washington, DC / New Delhi, India - Researchers at CDDEP, in collaboration with leading experts in the field, have produced the "Infectious Diseases in the South-East Asia Region" report, which examines cross-boundary challenges in communicable disease control in countries in the South-and South-East Asia region. The report emphasizes infectious diseases related to other sources of disease burden in the region and communicates overall trends in the health and economic burden they impose.
Despite substantial progress in recent years, which has seen reductions in deaths from HIV and malaria and an increase ...
2021-02-23
Researchers of the University of Helsinki have resolved for the first time, how the ultrafine particles of atmosphere effect on the climate and health.
Atmospheric air pollution kills more than 10,000 people every day. The biggest threat to human health has been assumed to be the mass accumulation of atmospheric particles with diameter smaller 2.5 μm: the higher the mass and loss of visibility, the bigger the threat.
The researchers of the Institute for Atmospheric and Earth System Research (INAR) at the University of Helsinki together with collaborators in China discovered that if we want to solve the accumulation of the biggest particles, we need to start with the smallest.
Until recent ...
2021-02-23
A new study has for the first time explored the rate at which the world's largest fish, the endangered whale shark, can recover from its injuries. The findings reveal that lacerations and abrasions, increasingly caused through collisions with boats, can heal in a matter of weeks and researchers found evidence of partially removed dorsal fins re-growing.
This work, published in the journal Conservation Physiology, comes at a critical time for these large sharks, that can reach lengths of up to 18 metres. Other recent studies have shown that as their popularity within the wildlife tourism sector increases, so do interactions with humans and boat traffic. As a result, these ...
2021-02-23
Huntington's disease is caused by a mutation in the Huntingtin gene (HTT), which appears in adults and features motor, cognitive and psychiatric alterations. The origin of this disease has been associated with the anomalous functioning of the mutated protein: mHTT, but recent data showed the involvement of other molecular mechanisms.
A new study conducted by the University of Barcelona has identified a type of ribonucleic acid (RNA) as a potential therapeutic target for the treatment of the disease. These are the small RNA, or sRNAs, molecules that do not code proteins but have important functions in the regulation of gene expression. According to the study, sRNAs would ...
2021-02-23
X-ray scans revolutionised medical treatments by allowing us to see inside humans without surgery. Similarly, terahertz spectroscopy penetrates graphene films allowing scientists to make detailed maps of their electrical quality, without damaging or contaminating the material. The Graphene Flagship brought together researchers from academia and industry to develop and mature this analytical technique, and now a novel measurement tool for graphene characterisation is ready.
The effort was possible thanks to the collaborative environment enabled by the Graphene Flagship European consortium, with participation by scientists from Graphene Flagship partners DTU, Denmark, IIT, Italy, Aalto University, Finland, AIXTRON, UK, imec, Belgium, Graphenea, Spain, Warsaw ...
2021-02-23
Seasons have an impact on our emotions and social life. Negative emotions are more subdued in the summer, whereas seasonal affective disorder rates peak during the darker winter months. Opioids regulate both mood and sociability in the brain.
In the study conducted at the Turku PET Centre, Finland, researchers compared how the length of daylight hours affected the opioid receptors in humans and rats.
"In the study, we observed that the number of opioid receptors was dependent on the time of the year the brain was imaged. The changes were most prominent in the brain regions that control emotions and sociability. The changes in the opioid receptors caused by the variation in the amount of daylight could be an important factor in seasonal affective disorder," ...
LAST 30 PRESS RELEASES:
[Press-News.org] The magic angle of twisted graphene
