Stretching changes the electronic properties of graphene
2021-06-29
(Press-News.org) The electronic properties of graphene can be specifically modified by stretching the material evenly, say researchers at the University of Basel. These results open the door to the development of new types of electronic components.
Graphene consists of a single layer of carbon atoms arranged in a hexagonal lattice. The material is very flexible and has excellent electronic properties, making it attractive for numerous applications - electronic components in particular.
Researchers led by Professor Christian Schönenberger at the Swiss Nanoscience Institute and the Department of Physics at the University of Basel have now studied how the material's electronic properties can be manipulated by mechanical stretching. In order to do this, they developed a kind of rack by which they stretch the atomically thin graphene layer in a controlled manner, while measuring its electronic properties.
Sandwiches on the rack
The scientists first prepared a "sandwich" comprising a layer of graphene between two layers of boron nitride. This stack of layers, furnished with electrical contacts, was placed on a flexible substrate.
The researchers then applied a force to the center of the sandwich from below using a wedge. "This enabled us to bend the stack in a controlled way, and to elongate the entire graphene layer," explained lead author Dr. Lujun Wang.
"Stretching the graphene allowed us to specifically change the distance between the carbon atoms, and thus their binding energy," added Dr. Andreas Baumgartner, who supervised the experiment.
Altered electronic states
The researchers first calibrated the stretching of the graphene using optical methods. They then used electrical transport measurements to study how the deformation of the graphene changes the electronic energies. The measurements need to be performed at minus 269°C for the energy changes to become visible.
"The distance between the atomic nuclei directly influences the properties of the electronic states in graphene," said Baumgartner, summarizing the results. "With uniform stretching, only the electron velocity and energy can change. The energy change is essentially the 'scalar potential' predicted by theory, which we have now been able to demonstrate experimentally."
These results could lead, for example, to the development of new sensors or new types of transistors. In addition, graphene serves as a model system for other two-dimensional materials that have become an important research topic worldwide in recent years.
INFORMATION:
ELSE PRESS RELEASES FROM THIS DATE:
2021-06-29
Mineral resources from Chile are of great importance to Germany. According to statistics from the World Bank, thousands of tons of valuable minerals are imported from the South American country every year, including raw materials for lithium-ion batteries. But their extraction causes ecological and social problems: "The use of the limited freshwater resources in northern Chile for mining regularly fuels conflicts with the local population," says Professor Thomas Kohl from KIT's Institute of Applied Geosciences (AGW). "Northern Chile is one of the driest regions on earth, but has extensive geothermal resources. With a novel type of plant, it is not only possible to generate electricity in a climate-friendly way, but also to extract ...
2021-06-29
When positioned strategically, garment seams sewn with conductive yarn can be used to accurately track body motion, according to computer scientists at the University of Bath in the UK. Best of all, these charged seams are able to respond to subtle movements that aren't picked up by popular fitness trackers, such as watches and wristbands.
In a new study, the Bath researchers found that clothing made with conductive seams can be analysed to identify the wearer's movements.
PhD student Olivia Ruston, who presented the work at the ACM Designing Interactive Systems conference this month, said: "There are lots of potential applications for conductive yarn in any activity where you want to identify and improve ...
2021-06-29
Mice are an important animal model of human vision due to the powerful genetic tools available in this species. However, mouse vision was thought to be different to that of humans because humans have a region of the retina specialized for fine details called the 'fovea' whereas mice do not. Researchers from the Netherlands Institute of Neuroscience (NIN) have shown that the visual cortex of mice does contain a region of enhanced visual sensitivity dubbed the 'focea', making the mouse a better model of human vision than previously expected. The findings were published ...
2021-06-29
Lithia, Florida -- June 29, 2021 -- Surgical resident training has traditionally occurred in a master-apprentice-type relationship, with graduated responsibilities until trainees are expected to perform procedures on their own. Given recent changes in the health care system, including reduced operating room time, increased difficulty of procedures and working hour restrictions, there is less time for residents to learn using traditional methods.
Researchers from the University of Manitoba and the Pan Am Clinic recently published a paper in the journal Arthroscopy, Sports Medicine, ...
2021-06-29
Aerosol generated by playing woodwind and brass instruments is less than that produced when vocalising (speaking and singing) and is no different than a person breathing, new research has found. The findings, published online in the journal Aerosol Science and Technology, could be crucial to developing a roadmap for lifting COVID-19 restrictions in the performing arts, which have been significantly restricted since the start of the pandemic.
The research project, known as PERFORM (ParticulatE Respiratory Matter to InForm Guidance for the Safe Distancing of PerfOrmeRs in a COVID-19 PandeMic), was supported by Public Health England, the Department for Digital, Culture, Media and Sport (DCMS), and UKRI and was carried out by a collaborative team from ...
2021-06-29
The death of neurons specialised in the synthesis of dopamine, one of the brain's main neurotransmissors, deteriorates the motor and cognitive capacities of those with Parkinson's disease. The loss of these neurons is related to alpha-synuclein aggregation. Recent studies show that oligomers, the initial aggregates of this protein, are the most pathogenic forms of α-synuclein and are responsible for the spreading of the disease in the brain.
Therefore, one of the more promising approaches in fighting this disorder consists in neutralising these oligomers and, thus, slow down the pathological progression. ...
2021-06-29
During the last twenty years, the trading in stock markets has undergone significant changes. Researchers from the University of Turku and the University of Palermo have investigated the role of high-frequency traders in the markets.
Technological evolution and innovations both in the technology used by stock exchanges and the resources of the traders using their services have made faster trading possible. As a result, high-frequency trading in sub millisecond scale has increased.
However, not everyone has the opportunity to use high-frequency trading, and generally, the scales can be anything from microseconds to tens of thousands of seconds. The role of high-frequency traders has given rise to broad debate over ...
2021-06-29
HERSHEY, Pa. -- A new study by researchers at Penn State College of Medicine indicates that people living with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) -- approximately 38 million worldwide -- are more likely to have suicidal thoughts and die from suicide than members of the general population. The researchers said that despite significant medical advancements related to HIV treatment and patients' quality of life, risk of suicide in these patients is high and health care providers should prioritize mental health screenings in this population.
According to the World Health Organization, roughly 800,000 people worldwide die from suicide annually. Among ...
2021-06-29
Tuesday, 29 June 2021 - New research has shown that early testing for blood clots in patients who had received the AstraZeneca/Oxford vaccine led to them being treated successfully, highlighting the need for heightened awareness of the risk among doctors.
The work, led by researchers from RCSI University of Medicine and Health Sciences and the National Coagulation Centre at St James's Hospital, is published in the British Journal of Haematology.
Unusual blood clots with low blood platelets have been recognised as a very rare complication of the AstraZeneca vaccine. However, with increased awareness, ...
2021-06-29
RUDN University chemists derived molecules that can assemble into complex structures using chlorine and bromine halogen atoms. They bind to each other as "velcro" - chlorine "sticks" to bromine, and vice versa. As a result supramolecules are assembled from individual molecules. The obtained substances will help to create supramolecules with catalytic, luminescent, conducting properties. The study is published in Mendeleev Communications.
Supramolecules are the structures made of several molecules. Individual molecules are combined, for example, by self-assembly or without external control. The resulting structure has properties that the molecules did not have individually. That is the way to create new materials, catalysts, molecular machines for ...
LAST 30 PRESS RELEASES:
[Press-News.org] Stretching changes the electronic properties of graphene
