. 24/7 Space News .
TECH SPACE
A new symmetry underlies the search for new materials
by Staff Writers
University Park PA (SPX) Nov 26, 2015


Each diffusion path for an oxygen atom (red) moving across a graphene ring composed of carbon atoms (gray ) is considered a 'distortion' and is indexed by a unique 'distortion symmetry group' indicated below each image. The symmetry group contains all the essential information about the properties of the material system as the diffusion occurs, including the ability to help determine the minimum energy pathway. In this case, the minimum energy pathway is when oxygen moves around the ring (right image) rather than across it (left image). Image courtesy Venkat Gopalan, Penn State. For a larger version of this image please go here.

A new symmetry operation developed by Penn State researchers has the potential to speed up the search for new advanced materials that range from tougher steels to new types of electronic, magnetic, and thermal materials. With further developments, this technique could also impact the field of computational materials design.

"In the physical sciences, making measurements can be time consuming and so you don't want to make unnecessary ones," said Venkat Gopalan, professor of materials science and engineering. "This is true for any material property - mechanical, electrical, optical, magnetic, thermal or any other. Knowing the symmetry group of a material can greatly reduce the number of measurements you have to make. "

Symmetry is pervasive throughout the physical universe and underlies the basic laws of physics. Gopalan gives a simple but scientifically accurate definition. "Symmetry is when doing something looks like doing nothing."

A circle has perfect symmetry, because if you rotate it by any number of degrees, it will look the same. Similarly, rotating a hexagon by sixty degrees leaves it exactly the same, but rotating it by a different amount does not. Anything that can be done that leaves an object looking the same is a symmetry operation.

In crystals, atoms are arranged in symmetrical patterns, like a cube of salt or a crystal of sugar or quartz. Symmetry groups tell scientists in how many different ways atoms can arrange in repeating patterns.

If they know which symmetry group a material falls into, they already know a great deal about the properties - mechanical, thermal, electrical and so forth - that material will have.

There are precisely 230 groups that explain how atoms can be arranged in space. These are symmetry "boxes" a material will fit into. If scientists are looking for a material with a certain property, such as the ability to be electrically polarized, they can look at materials only in that symmetry box and ignore all the boxes that cannot possibly contain polar materials.

Another symmetry operation, called time reversal, adds to the number of symmetry boxes available, and applies specifically to magnetic materials. This simply says that if time runs backwards, a material will either look the same or it won't.

In a paper published online in the journal Nature Communications, Gopalan and his coauthor and former Ph.D. student Brian VanLeeuwen report a new set of boxes called distortion symmetry groups that describes what happens when physical systems are perturbed by stresses, electric and magnetic fields or other forces, and change from one state to another.

"Distortions are the most common phenomenon in nature," Gopalan said. "A chemical reaction is a distortion, diffusion is a distortion, and a change in the atomic positions and electronic clouds within a material is a distortion. The symmetry that Brian and I discovered is like recording a movie of atoms and looking at its symmetry, whereas most symmetry operations are looking at one frame of a movie.

"We show that there is a huge family of problems that this will apply to, such as phase transitions - for example, water changing from a liquid to a solid or vibrations in molecules and solids. You will see symmetries you couldn't easily see before. Then we can quickly reduce the number of experiments we have to run or the number of computations that have to be done to find how a material will change under the effect of distortions."

VanLeeuwen and Gopalan's operation is already being applied by colleagues at Penn State working in computational materials design. One group is using the technique to understand and model the diffusion of hydrogen atoms in steel. Another group is incorporating it into a powerful computer code called Quantum Espresso, used by modelers around the globe.

"The first question we like to ask when a new material is discovered is how the atoms are arranged in space," said Ismaila Dabo, assistant professor of materials science and engineering, and one of the developers of Quantum Espresso.

"Symmetries provide a powerful language to explain such atomic arrangements and their distortions close to equilibrium. But when the distortions are so large that they bring the atoms far away from equilibrium, there was no clear way to describe materials transformation, making it difficult to classify critical phenomena like phase transitions or grain boundary motions. This work gives an admirably elegant and much needed answer to that question."

Proteins are complex crystals that change when a drug molecule attaches to them. But current drug discovery is very computationally and experimentally intensive. Gopalan feels this technique might someday be useful for reducing the number of trials required.

"Biology is all about distortions of biomolecules towards performing a biological function," he said. "This will be worthwhile knowledge to them. Someday this could be very useful, but biology is highly complex involving hundreds of atoms in a unit cell. We are not yet sure if these ideas could make an impact there, but we plan to try. My goal is to take this and apply it to a variety of simpler problems first."

VanLeeuwen said that many technologies that are limited by materials properties could benefit by applying this method to find new materials. This includes stronger and lighter alloys for space exploration and fuel efficiency, better sensors for healthcare and greater performance from turbines for more energy production.

"Nature always takes the path of least resistance. Knowing this path allows us to calculate tremendously important materials properties. These properties are critical to the function of a very wide range of technologies, from making it possible for an ultrasound to detect a life-threatening heart condition to preventing nuclear reactors from melting down," VanLeeuwen said.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Penn State
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
TECH SPACE
From nanocrystals to earthquakes, solid materials share similar failure characteristics
Chicago IL (SPX) Nov 23, 2015
Apparently, size doesn't always matter. An extensive study by an interdisciplinary research group suggests that the deformation properties of nanocrystals are not much different from those of the Earth's crust. "When solid materials such as nanocrystals, bulk metallic glasses, rocks, or granular materials are slowly deformed by compression or shear, they slip intermittently with slip-avala ... read more


TECH SPACE
Gaia's sensors scan a lunar transit

SwRI scientists explain why moon rocks contain fewer volatiles than Earth's

All-female Russian crew starts Moon mission test

Russian moon mission would need 4 Angara-A5V launches

TECH SPACE
ExoMars prepares to leave Europe for launch site

Tracking down the 'missing' carbon from the Martian atmosphere

Mars to lose its largest moon, Phobos, but gain a ring

Study: Mars to become a ringed planet following death of its moon

TECH SPACE
Aerojet Rocketdyne tapped for spacecraft's crew module propulsion

Brits Aim for the Stars with Big Bucks on Offer to Conquer Final Frontier

XCOR develops Lynx Simulator

Orion ingenuity improves manufacturing while reducing mass

TECH SPACE
China's scientific satellites to enter uncharted territory

China to launch Dark Matter Satellite in mid-December

China to better integrate satellite applications with Internet

China's satellite expo opens

TECH SPACE
Russian-US Space Collaboration Intact Despite Chill in Bilateral Ties

ISS EarthKAM ready for student imaging request

Partners in Science: Private Companies Conduct Valuable Research on the Space Station

SAGE III Leaves Langley for Journey to ISS

TECH SPACE
Vega receives the LISA Pathfinder payload for its December 2 flight

Rocket launch demonstrates new capability for testing technologies

Rocket launch demonstrates new capability for testing technologies

NASA calls on SpaceX to send astronauts to ISS

TECH SPACE
Retro Exo and Its Originators

How DSCOVR Could Help in Exoplanet Hunting

Forming planet observed for first time

UA researchers capture first photo of planet in making

TECH SPACE
Bringing the chaos in light sources under control

SSL selected to provide new high throughput satellite to Telesat

Puffed rice compaction unveils new materials science phenomenon

Advancing the Design and Modeling of Complex Systems









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.