Tunneling Across a Ferroelectric

Jul 14, 2006

University of Nebraska-Lincoln physicist Evgeny Tsymbal's groundbreaking identification of an emerging research field in electronic devices earned publication this week in Science magazine.

Tsymbal, a professor of physics and astronomy at UNL and a specialist in spin electronics at UNL's Materials Research Science and Engineering Center and the Nebraska Center for Materials and Nanoscience, identified and provided an overview on electron tunneling through ultra-thin layers of spontaneously polarized materials as an important new area for applied physics research.

In "Tunneling Across a Ferroelectric," in the July 14 issue of Science, published by the American Association for the Advancement of Science, Tsymbal and collaborator Hermann Kohlstedt of the Research Center in Julich, Germany, highlighted emerging research on ferroelectric tunnel junctions.

The phenomenon of electron "tunneling" through nonconductive barriers has been known since the advent of quantum physics. But Tsymbal noted in his article that new research and experimental collaboration on practical applications of the theory are becoming likely and necessary, and that new studies will open an avenue for the development of new electronic devices.

Tsymbal described ferroelectric tunnel junctions this way: Metal conducts electric currents and insulators block them. But if an ultra-thin layer of an insulating material about one nanometer thick is placed between two metal electrodes and a voltage is applied, electrons are able to tunnel through the barrier. Using a ferroelectric material as the insulating barrier layer adds new functional property to a tunnel junction because of the spontaneous polarization of the material. Ferroelectric tunnel junctions could be used for different applications such as nonvolatile memories for computers.

"Our prediction is that it's possible to change significantly the resistance of this tunnel junction by changing the polarization orientation," Tsymbal said. "That's in theory. In order to realize the prediction in practice, many things have to be done: Scientists must learn how to grow very thin ferroelectrics and control their properties. There are several experimental groups worldwide who demonstrate that this is possible."

Tsymbal and his group will continue the research to deepen the understanding of the theory in the materials and devices, and will work to join researchers at UNL in physics, chemistry and engineering to collaborate in this field.

He has visited a major computer manufacturer and finds that researchers are interested in the concept and the idea of combining ferroelectric and magnetic materials to broaden opportunities for future technologies. For example, the coupling between ferroelectricity and magnetism in a single device may yield entirely new device paradigms, such as transducers converting between magnetic and electric fields or electric field-controlled magnetic data storage.

"There are many different possibilities that we can't even imagine at the moment -- maybe 20 years from now -- which might be feasible due to additional functionalities offered by the present ferroelectric junctions," Tsymbal said.

"It's an emerging field of promising research. This article may excite people and stimulate further research on this subject. The fact that a representative of the University of Nebraska is publishing the topic in Science is definitely a recognition in the worldwide solid state physics research community of the expertise at Nebraska."

Much of Tsymbal's research interests are in theory of electronic transport in nanostructures. He also leads a research group in condensed matter theory and coordinates an interdisciplinary research group in the Materials Research Science and Engineering Center. His research group has also published several papers on tunnel junctions in Physical Review Letters, one of the most prestigious physics journals.

Source: University of Nebraska-Lincoln

Explore further: The birth of topological spintronics

add to favorites email to friend print save as pdf

Related Stories

How Kindle Unlimited compares with Scribd, Oyster

12 hours ago

Amazon is the latest—and largest—company to offer unlimited e-books for a monthly fee. Here's how Kindle Unlimited, which Amazon announced Friday, compares with rivals Scribd and Oyster.

NASA sees powerful thunderstorms in Tropical Storm Matmo

12 hours ago

Strong thunderstorms reaching toward the top of the troposphere circled Tropical Storm Matmo's center and appeared in a band of thunderstorms on the storm's southwestern quadrant. Infrared imagery from NASA's ...

ISS 'space truck' launch postponed: Arianespace

14 hours ago

The July 24 launch of a robot ship to deliver provisions to the International Space Station has been postponed "for a few days", space transport firm Arianespace said Friday.

Recommended for you

IHEP in China has ambitions for Higgs factory

26 minutes ago

Who will lay claim to having the world's largest particle smasher?. Could China become the collider capital of the world? Questions tease answers, following a news story in Nature on Tuesday. Proposals for ...

The physics of lead guitar playing

1 hour ago

String bends, tapping, vibrato and whammy bars are all techniques that add to the distinctiveness of a lead guitarist's sound, whether it's Clapton, Hendrix, or BB King.

The birth of topological spintronics

2 hours ago

The discovery of a new material combination that could lead to a more efficient approach to computer memory and logic will be described in the journal Nature on July 24, 2014. The research, led by Penn S ...

The electric slide dance of DNA knots

6 hours ago

DNA has the nasty habit of getting tangled and forming knots. Scientists study these knots to understand their function and learn how to disentangle them (e.g. useful for gene sequencing techniques). Cristian ...

User comments : 0