PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Vibrating 2D materials

Vibrating 2D materials
2021-02-11
(Press-News.org) Current electronic components in computers, mobile phones and many other devices are based on microstructured silicon carriers. However, this technology has almost reached its physical limits and the smallest possible structure sizes.

Two-dimensional (2D) materials are therefore being intensively researched. One can imagine these materials as extremely thin films consisting of only one layer of atoms. The best known is graphene, an atomically thin layer of graphite. For its discovery, Andre Geim and Konstantin Novoselov received the Nobel Prize in Physics in 2010.

While graphene consists purely of carbon, there are numerous other 2D compounds that are characterised by special optical and electronic properties. Countless potential applications of these compounds are currently being researched, for example for use in solar cells, in micro- and optoelectronics, in composite materials, catalysis, in various types of sensors and light detectors, in biomedical imaging or in the transport of drugs in the organism.

Light energy can make 2D materials vibrate

For the function of these 2D compounds, one exploits their special properties. "It is important to know how they react to excitation with light," says Professor Tobias Brixner, head of the Chair of Physical Chemistry I at Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany.

In principle, 2D materials are electronically excited just like ordinary silicon solar cells when sufficient light energy hits them. However, the energy can cause the atomically thin layer to vibrate at the same time. This in turn influences the optoelectronic properties.

Strength of exciton-phonon coupling is difficult to determine

Until now, it was unknown how strongly light excites such oscillations in a 2D material at room temperature. Now, in an international collaboration, a team led by Tobias Brixner has succeeded for the first time in determining the strength of the oscillation excitation upon light absorption in a 2D material - namely in a "transition metal dichalcogenide" - at room temperature.

"This quantity, known in technical jargon as exciton-phonon coupling strength, is difficult to determine because at room temperature the absorption spectrum is very much 'smeared out' and no individual spectral lines can be separated," says the JMU physicist and physical chemist.

Postdoc developed coherent 2D microscopy

Now, however, postdoctoral researcher Dr Donghai Li in Würzburg has developed the method of "coherent 2D microscopy". It combines the spatial resolution of a microscope with the femtosecond time resolution of ultra-short laser pulses and with the multi-dimensional frequency resolution. This allowed Li to quantify the influence of the oscillations.

Brixner explains: "Surprisingly, it turned out that the exciton-phonon coupling strength in the investigated material is much greater than in conventional semiconductors. This finding is helpful in the further development of 2D materials for specific applications."

INFORMATION:

The members of the international research team

Research teams led by Andrea Ferrari from the Graphene Center at Cambridge University (UK), Giancarlo Soavi from the Abbe Center of Photonics at the University of Jena and Giulio Cerullo from Politecnico di Milano (Italy) were involved in the study, which appeared in the journal Nature Communications on 11.02.2021.


[Attachments] See images for this press release:
Vibrating 2D materials

ELSE PRESS RELEASES FROM THIS DATE:

Wafer-scale production of graphene-based photonic devices

Wafer-scale production of graphene-based photonic devices
2021-02-11
Our world needs reliable telecommunications more than ever before. However, classic devices have limitations in terms of size and cost and, especially, power consumption - which is directly related to greenhouse emissions. Graphene could change this and transform the future of broadband. Now, Graphene Flagship researchers have devised a wafer-scale fabrication technology that, thanks to predetermined graphene single-crystal templates, allows for integration into silicon wafers, enabling automation and paving the way to large scale production. This work, published in the prestigious journal ACS Nano, is a great example of a collaboration fostered by the ...

- How we sleep and experience psychological symptoms during pandemic

2021-02-11
During the first confinement (18 March to 10 May 2020), people who reported worse sleep quality during a night also reported an increase in negative mood, psychotic-type like experiences and somatic complaints on the next day. Furthermore, daily reports of deaths caused by Covid-19 predicted psychological symptoms on the same day and sleep quality the following night. This is the result of research carried out in three countries (Belgium, Hungary, Spain) under direction of Peter Simor with researchers at the Université libre de Bruxelles (ULB), Rebeca Sifuentes-Ortega, Ariadna Albajara Saenz, Oumaïma Benkirane, Anke Van Roy and Philippe Peigneux from the CRCN (Center for Research in Cognition and Neurosciences) and the UNI (ULB Neurosciences Institute) ...

Smartphone app to change your personality

2021-02-11
Personality traits such as conscientiousness or sociability are patterns of experience and behavior that can change throughout our lives. Individual changes usually take place slowly as people gradually adapt to the demands of society and their environment. However, it is unclear whether certain personality traits can also be psychologically influenced in a short-term and targeted manner. Researchers from the universities of Zurich, St. Gallen, Brandeis, Illinois, and ETH Zurich have now investigated this question using a digital intervention. In their study, around 1,500 participants were provided with a specially developed smartphone app for three months and the researchers then assessed whether and ...

RUDN University mathematician suggested a scheme for solving telegraph equations

RUDN University mathematician suggested a scheme for solving telegraph equations
2021-02-11
A mathematician from RUDN University suggested a stable difference scheme for solving inverse problems for elliptic-telegraph and differential equations that are used to describe biological, physical, and sociological processes. The results of the study were published in the Numerical Methods for Partial Differential Equations journal. Elliptic equations are a class of differential equations in partial derivatives that are used, among other things, to model time-independent processes. Telegraph equations are presented in a nonstationary form. They were initially obtained for a telegraph communication line, but today they are also used to model the movement of insects, the flow of blood ...

Ionic liquid uniformly delivers chemotherapy to tumors while destroying cancerous tissue

2021-02-11
PHOENIX -- A Mayo Clinic team, led by Rahmi Oklu, M.D., Ph.D., a vascular and interventional radiologist at Mayo Clinic, in collaboration with Samir Mitragotri, Ph.D., of Harvard University, report the development of a new ionic liquid formulation that killed cancer cells and allowed uniform distribution of a chemotherapy drug into liver tumors and other solid tumors in the lab. This discovery could solve a problem that has long plagued drug delivery to tumors and provide new hope to patients with liver cancer awaiting a liver transplant. The preclinical study results are published in Science Translational Medicine. Dr. Oklu, study author and director of Mayo Clinic's ...

Emissions of banned ozone-depleting substance back on decline

Emissions of banned ozone-depleting substance back on decline
2021-02-11
Two international studies of a consortium including more than a dozen institutions the world over, including Empa, published today in the journal Nature show levels of CFC-11 emissions, one of many chlorofluorocarbon (CFC) chemicals once widely used in refrigerators and insulating foams, are back on the decline - less than two years after their shock resurgence in the wake of suspected rogue production in eastern China was widely publicized. "The findings are very welcome news and hopefully mark an end to a disturbing period of apparent regulatory breaches", says Luke Western from the University of Bristol, a ...

Small is big: the need for a holistic approach to manage cerebral small vessel disease

Small is big: the need for a holistic approach to manage cerebral small vessel disease
2021-02-11
Cerebral small vessel disease (SVD) is characterized by damage to the blood vessels and parenchyma in the brain. It presents as a multitude of symptoms, which makes the diagnosis difficult. Matters are complicated further when SVD sets in along with other comorbidities with similar symptoms. Therefore, accurate diagnosis at an early stage of disease progression helps in defining better prognosis and management strategies for patients with cerebral SVD. A team of researchers from the United Kingdom set out to review more than 10,000 studies on clinical diagnosis, risk factors, progression, and intervention ...

A study analyses breakfast-related advertising in Mediterranean countries

2021-02-11
Experts have spent decades warning us about the rising rates of childhood obesity, which has become an epidemic among recent generations in many places around the world, including Spain. The transition from the traditional Mediterranean diet to the consumption of processed foods with low nutritional value is a key contributor, with child-targeted advertising also partly to blame. According to the Breakfast Food Advertisements in Mediterranean Countries: Products' Sugar Content in Adverts from 2015 to 2019 report produced by UOC Faculty of Information and Communication Sciences professor and researcher, Mireia Montaña, the majority of breakfast products ...

Swirlonic super particles baffle physicists

2021-02-11
In recent years, active, self-propelled particles have received growing interest amongst the scientific community. Examples of active particles and their systems are numerous and very diverse, ranging from bacterium films to flocks of birds or human crowds. These systems can demonstrate unusual behavior, which is challenging to understand or model. To this end, large-scale models of active particles were being scrutinised by experts at Leicester, in order to understand basic principles underlying active particle dynamics and apply them in a scenario of an evacuation strategy for customers in crowded place. Unexpectedly, the 'super-particles' milling in a circular motion were stumbled upon ...

The power of groupthink: Study shows why ideas spread in social networks

2021-02-11
There's a reason that ideas--even erroneous ones--catch fire on social media or in popular culture: groupthink. New research co-authored by Berkeley Haas Asst. Prof. Douglas Guilbeault shows that large groups of people all tend to think alike, and also illustrates how easily people's opinions can be swayed by social media--even by artificial users known as bots. In a series of experiments, published in the journal Nature Communications, Guilbeault and co-authors Damon Centola of the University of Pennsylvania and Andrea Baronchelli of City University London created an online game that asked numerous people to identify ...

LAST 30 PRESS RELEASES:

Thirty-year mystery of dissonance in the “ringing” of black holes explained

Less intensive works best for agricultural soil

Arctic rivers project receives “national champion” designation from frontiers foundation

Computational biology paves the way for new ALS tests

Study offers new hope for babies born with opioid withdrawal syndrome

UT, Volkswagen Group of America celebrate research partnership

New Medicare program could dramatically improve affordability for cancer drugs – if patients enroll

Are ‘zombie’ skin cells harmful or helpful? The answer may be in their shapes

University of Cincinnati Cancer Center presents research at AACR 2025

Head and neck, breast, lung and survivorship studies headline Dana-Farber research at AACR Annual Meeting 2025

AACR: Researchers share promising results from MD Anderson clinical trials

New research explains why our waistlines expand in middle age

Advancements in muon detection: Taishan Antineutrino Observatory's innovative top veto tracker

Chips off the old block

Microvascular decompression combined with nerve combing for atypical trigeminal neuralgia

Cutting the complexity from digital carpentry

Lung immune cell type “quietly” controls inflammation in COVID-19

Fiscal impact of expanded Medicare coverage for GLP-1 receptor agonists to treat obesity

State and sociodemographic trends in US cigarette smoking with future projections

Young adults drive historic decline in smoking

NFCR congratulates Dr. Robert C. Bast, Jr. on receiving the AACR-Daniel D. Von Hoff Award for Outstanding Contributions to Education and Training in Cancer Research

Chimpanzee stem cells offer new insights into early embryonic development

This injected protein-like polymer helps tissues heal after a heart attack

FlexTech inaugural issue launches, pioneering interdisciplinary innovation in flexible technology

In Down syndrome mice, 40Hz light and sound improve cognition, neurogenesis, connectivity

Methyl eugenol: potential to inhibit oxidative stress, address related diseases, and its toxicological effects

A vascularized multilayer chip reveals shear stress-induced angiogenesis in diverse fluid conditions

AI helps unravel a cause of Alzheimer's disease and identify a therapeutic candidate

Coalition of Autism Scientists critiques US Department of Health and Human Services Autism Research Initiative

Structure dictates effectiveness, safety in nanomedicine

[Press-News.org] Vibrating 2D materials