Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Drexel Researchers Open Path to Finding Rare, Polarized Metals

03.04.2014

Drexel University researchers are turning some of the basic tenets of chemistry and physics upside down to cut a trail toward the discovery of a new set of materials. They’re called “polar metals” and, according to many of the scientific principles that govern the behavior of atoms, they probably shouldn’t exist.

James Rondinelli, PhD, a professor in the College of Engineering, and Danilo Puggioni, PhD, a postdoctoral researcher in the College, have shed light on this rare breed of electrically conductive polar metal—whose atomic makeup actually has more in common with a drop of water than a flake of rust—using an advanced computing method called density functional theory.


Drexel materials scientists predicted the existence of a polarized metal called strontium-calcium ruthenate.

This automated system of virtual chemical match-making sifts through volumes of structural chemistry data to churn out combinations of elements that could exist as stable compounds. Rondinelli and Puggioni, both members of Drexel’s Material’s Theory and Design Group in the College's Materials Science Engineering department, worked through a step-by-step process to isolate shared features of known polar metals, thus creating a way to classify them.

“We sought first to classify all known compounds and look for commonalities and ways to systematically describe them,” Rondinelli said. “By creating the classification scheme we identified the key features. That knowledge was formulated into a working principle that allowed us to predict a new compound using quantum mechanical calculations.”

These metals are considered rare because of their unusual atomic and chemical structure, specifically, an imbalanced distribution of electrons in a material with metal cations and oxygen. Most metallic materials have an even or symmetric distribution of electrons, in other words it does not have positively and negatively charged poles. But these asymmetric polar metals, appear to be an exception to the rule.    

“They challenge our notions of what it means for a material to be a metal or to be polar,” Rondinelli said. “By polar, I mean just like the water molecule, which has an asymmetric distribution of charge. It’s nearly the same case here, where the material we predict is polar, but it is simultaneously metallic owing to mobile electrons, rather than bound electrons.”

Scientists have hypothesized the existence of polar metals, dubbed “metallic ferroeletrics” by Nobel Laureate Phil Anderson, since the 1960s -but with little theoretical understanding of how to discover them. Since then, researchers have essentially stumbled upon about 30 metals with asymmetric charge distributions.  

More than half a century later, Rondinelli and Puggioni were able to examine the crystal structure of these known polar metals, and show that the geometric arrangement of atoms is key to understanding their asymmetric charge distribution. This information, in turn, will make it possible for materials scientists to discover more compounds.

Putting their theory to the test, the duo designed a polar metal of their own. The material, chemically termed strontium-calcium ruthenate, (Sr,Ca)Ru­O6, is currently in the theoretical stage, but Rondinelli and Puggioni are working with experimental groups around the country to produce the compound in a laboratory.

While it’s too early to predict what applications these materials are ideally suited for, other materials in this class of polar metals are superconducting—they are able to conduct electricity with zero resistance—so they could find use in a variety of advanced electronic and thermal devices. The pair’s research was funded by the Army Research Office’s Young Investigator Program and was recently published in Nature Communications.

“The way these materials behave and the reasons for their stability are rather unconventional, yet our classification scheme provides a general design strategy that could guide the discovery and realization of many more polar metals,” said Rondinelli. “I don’t believe these materials are as rare as is currently thought despite their counterintuitive nature; researchers may have simply been looking in the wrong places.”

Puggioni D. & Rondinelli J.M. (2014). Designing a robustly metallic noncenstrosymmetric ruthenate oxide with large thermopower anisotropy, Nature Communications, 5 DOI:

News Media Contact

Britt Faulstick

News Officer, University Communications

britt.faulstick@drexel.edu
Phone: 215-895-2617
Mobile: 215-796-5161

Britt Faulstick | EurekAlert!
Further information:
http://drexel.edu/now/news-media/releases/archive/2014/April/PolarMetals/

Further reports about: Electrons Metals atomic structure classification compounds

More articles from Materials Sciences:

nachricht Researchers devise microreactor to study formation of methane hydrate
23.08.2017 | NYU Tandon School of Engineering

nachricht Meter-sized single-crystal graphene growth becomes possible
22.08.2017 | Science China Press

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>