Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Theorists predict new forms of exotic insulating materials

07.02.2014
Topological insulators could exist in 6 new types not seen before

Topological insulators — materials whose surfaces can freely conduct electrons even though their interiors are electrical insulators — have been of great interest to physicists in recent years because of unusual properties that may provide insights into quantum physics. But most analysis of such materials has had to rely on highly simplified models.

Now, a team of researchers at MIT has performed a more detailed analysis that hints at the existence of six new kinds of topological insulators. The work also predicts the materials' physical properties in sufficient detail that it should be possible to identify them unambiguously if they are produced in the lab, the scientists say.

The new findings are reported this week in the journal Science by MIT professor of physics Senthil Todadri, graduate student Chong Wang, and Andrew Potter, a former MIT graduate student who is now a postdoc at the University of California at Berkeley.

"In contrast to conventional insulators, the surface of the topological insulators harbors exotic physics that are interesting both for fundamental physics, and possibly for applications," Senthil says. But attempts to study the properties of these materials have "relied on a highly simplified model in which the electrons inside the solid are treated as though they did not interact with each other." New analytical tools applied by the MIT team now reveal "that there are six, and only six, new kinds of topological insulators that require strong electron-electron interactions."

"The surface of a three-dimensional material is two-dimensional," Senthil says — which explains why the electrical behavior of the surface of a topological insulator is so different from that of the interior. But, he adds, "The kind of two-dimensional physics that emerges [on these surfaces] can never be in a two-dimensional material. There has to be something inside, otherwise this physics will never occur. That's what's exciting about these materials," which reveal processes that don't show up in other ways.

In fact, Senthil says, this new work based on analysis of such surface phenomena shows that some previous predictions of phenomena in two-dimensional materials "cannot be right."

Since this is a new finding, he says, it is too soon to say what applications these new topological insulators might have. But the analysis provides details on predicted properties that should allow experimentalists to begin to understand the behavior of these exotic states of matter.

"If they exist, we know how to detect them," Senthil says of these new phases. "And we know that they can exist." What this research doesn't yet show, however, is what these new topological insulators' composition might be, or how to go about creating them.

The next step, he says, is to try to predict "what compositions might lead to" these newly predicted phases of topological insulators. "It's an open question now that we need to attack."

The research was supported by the U.S. Department of Energy, the National Science Foundation, and the Simons Foundation.

Written by David Chandler, MIT News Office

David Chandler | EurekAlert!
Further information:
http://www.mit.edu

More articles from Materials Sciences:

nachricht New materials: Growing polymer pelts
19.11.2018 | Karlsruher Institut für Technologie (KIT)

nachricht Why geckos can stick to walls
19.11.2018 | Jacobs University Bremen gGmbH

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First diode for magnetic fields

Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.

Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...

Im Focus: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Helping to Transport Proteins Inside the Cell

21.11.2018 | Life Sciences

Meta-surface corrects for chromatic aberrations across all kinds of lenses

21.11.2018 | Power and Electrical Engineering

Removing toxic mercury from contaminated water

21.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>