Navigation Links
Columbia engineering team discovers graphene's weakness
Date:11/30/2010

New York, NY November 29, 2010 In 2008, experiments at The Fu Foundation School of Engineering and Applied Science at Columbia University established pure graphene, a single layer of graphite only one atom thick, as the strongest material known to mankind. This raised a question for Chris Marianetti, Assistant Professor in Columbia Engineering's Department of Applied Physics and Applied Mathematics: how and why does graphene break?

Using quantum theory and supercomputers, Marianetti has revealed the mechanisms of mechanical failure of pure graphene under tensile stress. In a paper recently accepted for publication in the journal Physical Review Letters, he shows that, when graphene is subject to strain equal in all directions, it morphs into a new structure which is mechanically unstable.

Marianetti says this failure mechanism is a novel soft-mode phonon instability. A phonon is a collective vibrational mode of atoms within a crystal, similar to a wave in a liquid. The fact that a phonon becomes "soft" under tensile strain means that the system can lower its energy by distorting the atoms along the vibrational mode and transitioning to a new crystalline arrangement. Under sufficient strain, graphene develops a particular soft-mode that causes the honeycomb arrangement of carbon atoms to be driven towards isolated hexagonal rings. This new crystal is structurally weaker, resulting in the mechanical failure of the graphene sheet.

"This is exciting on many different levels," Marianetti notes. "Soft modes were first recognized in the 1960s in the context of ferroelectric phase transitions, but they have never been directly linked to fracture. Typically, defects in a material will always cause failure to happen prematurely, but the pristine nature of graphene allows one to test our prediction. We have already outlined some interesting new experiments to directly observe our theoretical prediction of the soft mode."

Marianetti added that this is the first time a soft optical phonon has ever been linked to mechanical failure and that therefore it is likely that this novel failure mechanism is not exclusive to graphene but may be prevalent in other very thin materials. "With nanotechnology becoming increasingly ubiquitous, understanding the nature of mechanical behavior in low dimensional systems such as graphene is of great importance. We think strain may be a means to engineer the properties of graphene, and therefore understanding its limits is critical." The research was funded by the National Science Foundation.

Marianetti's research interests lie in the use of classical and quantum mechanics to model the behavior of materials at the atomic scale. In particular, he is focused on applying these techniques to materials with potential for energy storage and conversion. Current applications in his research program range from nuclear materials such as plutonium to rechargeable battery materials such as cobalt oxides.


'/>"/>

Contact: Holly Evarts
holly@engineering.columbia.edu
212-854-3206
Columbia University
Source:Eurekalert

Related biology technology :

1. OncoGenex Pharmaceuticals Named Life Sciences Company of the Year by LifeSciences British Columbia
2. Leading North American Emergency Medical Services Provider British Columbia Ambulance Service Selects NICE Inform for Improved Service
3. American Oriental Bioengineering Announces Participation in September Investor Conferences
4. Online Systems Engineering Master's Program Attracts Engineers from Fortune 500 Firms
5. NSF awards 14 materials research science and engineering centers
6. Genetic Engineering & Biotechnology News reports on growing role of molecular diagnostics
7. Genstruct Expands Team with New VP of Engineering
8. Engineering nanoparticles for maximum strength
9. American Oriental Bioengineering Completes Two Acquisitions
10. American Oriental Bioengineering, Inc. to Report Third Quarter 2008 Financial Results
11. American Oriental Bioengineering Announces Participation in November Investor Conferences
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/26/2017)... ... April 25, 2017 , ... LABS, Inc. (LABS) announced ... added to its extensive test menu: Nucleic Acid Testing (NAT) for ZIKV; and Enzyme ... only able to offer NAT screening for blood donors under an Investigational New Drug ...
(Date:4/25/2017)... ... , ... As part of the Stago EdVantage Virtual University Virtual ... in order to illuminate this clinical problem for people unfamiliar with the topic. , ... a high degree of morbidity and mortality. DIC is a confusing disorder from both ...
(Date:4/25/2017)... California (PRWEB) , ... April 25, 2017 , ... ... Analytical Services and Metrology Partners.     , Covalent’s Analytical Services unit provides ... samples can be measured within 24 hours of receipt. There are no price ...
(Date:4/21/2017)... ... 21, 2017 , ... Having worked on the design of the innovative ... it to top lab design architects from around the country at the Lab Design ... Design and Engineering Greg Casey will be at the show, where they will highlight ...
Breaking Biology Technology:
(Date:4/5/2017)... April 5, 2017  The Allen Institute for Cell ... Explorer: a one-of-a-kind portal and dynamic digital window into ... data, the first application of deep learning to create ... cell lines and a growing suite of powerful tools. ... these and future publicly available resources created and shared ...
(Date:4/4/2017)... , April 4, 2017   EyeLock LLC , ... that the United States Patent and Trademark Office (USPTO) ... covers the linking of an iris image with a ... and represents the company,s 45 th issued patent. ... is very timely given the multi-modal biometric capabilities that ...
(Date:3/30/2017)... , March 30, 2017 The research team ... for three-dimensional (3D) fingerprint identification by adopting ground breaking 3D fingerprint ... new realm of speed and accuracy for use in identification, crime ... affordable cost. ... A ...
Breaking Biology News(10 mins):