Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How do atoms vibrate in graphene nanostructures?

12.08.2019

Innovative new electron spectroscopy technique pushes the limits of nanospectroscopy for materials design

In order to understand advanced materials like graphene nanostructures and optimize them for devices in nano-, opto- and quantum-technology it is crucial to understand how phonons - the vibration of atoms in solids - influence the materials' properties.


Schematic representation of local lattice vibrations in graphene excited by a wavefront of transmitted fast electrons.

Credit:© Ryosuke Senga, AIST

Researchers from the University of Vienna, the Advanced Institute of Science and Technology in Japan, the company JEOL and La Sapienza University in Rome have developed a method capable to measure all phonons existing in a nanostructured material.

This is a breakthrough in the analysis of nanoscale functional materials and devices. With this pilot experiment using graphene nanostructures these researchers have shown the uniqueness of their approach, which will be published in the latest issue of Nature.

Important thermal, mechanical, optoelectronic and transport characteristics of materials are ruled by phonons: the propagating atomic vibrational waves. It is then inferable that the determination of such extended atomic vibrations is crucial for the optimization of nanoelectronic devices.

The current available techniques use optical methods as well as inelastic electron-, x-ray- and neutron scattering. Despite its scientific importance in the last decade, none of these methods has been able to determine all phonons of a freestanding monolayer of two dimensional (2D) materials such as graphene and their local variations within a graphene nanoribbon, which are in turn used as active elements in nano- and optoelectronics.

The new limits of nanospectroscopy

An international research team of leading experts in electron spectroscopy led by Thomas Pichler at the University of Vienna, theoretical spectroscopy led by Francesco Mauri at La Sapienza University in Rome and electron microscopy led by Kazu Suenaga at the AIST Tsukuba in Japan, together with the Japanese company JEOL have presented an original method applying it to graphene nanostructures as model: "high resolution electron spectroscopy inside an electron microscope with enough sensitivity to measure even an atomic monolayer".

In this way they could for the first time determine all vibrational modes of freestanding graphene as well as the local extension of different vibrational modes in a graphene nanoribbon. This new method, which they called "large q mapping" opens entirely new possibilities to determine the spatial and momentum extension of phonons in all nanostructured as well as two dimensional advanced materials.

These experiments push the limits of nanospectroscopy approaching the limits of Heisenbergs uncertainty principle and demonstrates new possibilities to study local vibration modes at the nanometer scale down to individual monolayers.

New electron nanospectrometer as "table top" synchrotron

"The direct experimental proof of the full spatial and momentum resolved mapping of local vibrations of all materials including even monolayer 2D materials and nanoribbons will enable us to fully disentangle different vibration modes and their momentum transfers at non-perfect structures such as edges or defects, which are extremely important to understand and optimize the local properties of a material", explains one of the leading authors, Ryosuke Senga.

This study of "High q-Mapping Of Vibrations" in the electron microscope opens a new pathway of nanospectroscopy of all materials combining spatial and momentum resolved measurements. This has been the biggest challenge regarding the combination of microscopy and spectroscopy, since the spatial and momentum resolutions are compensated due to the limit of Heisenbergs uncertainty principle.

"We believe that our methodology will boost vast research in material science and will push high resolution electron spectroscopy in electron microscopy to the next level, to be envisaged as a true table top synchrotron", says Thomas Pichler from the University of Vienna.

###

The work was supported by FWF, the EU and JSPS.

Publication in "Nature":

"Position and momentum mapping of vibrations in graphene nanostructures", Ryosuke Senga, Kazu Suenaga, Paolo Barone, Shigeyuki Morishita, Francesco Mauri, Thomas Pichler Nature, 2019 DOI: 10.1038/s41586-019-1477-8

Media Contact

Thomas Pichler
thomas.pichler@univie.ac.at
43-664-602-775-1466

 @univienna

http://www.univie.ac.at/en/

Thomas Pichler | EurekAlert!
Further information:
https://www.nature.com/articles/s41586-019-1477-8
http://dx.doi.org/10.1038/s41586-019-1477-8

More articles from Materials Sciences:

nachricht A robot and software make it easier to create advanced materials
06.12.2019 | Rutgers University

nachricht First field measurements of laughing gas isotopes
05.12.2019 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Solving the mystery of carbon on ocean floor

06.12.2019 | Earth Sciences

Chip-based optical sensor detects cancer biomarker in urine

06.12.2019 | Life Sciences

A platform for stable quantum computing, a playground for exotic physics

06.12.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>