Featured Research

from universities, journals, and other organizations

Engineering atomic interfaces for new electronics

Date:
February 22, 2011
Source:
University of Wisconsin-Madison
Summary:
Most people cross borders such as doorways or state lines without thinking much about it. Yet not all borders are places of limbo intended only for crossing. Some borders, like those between two materials that are brought together, are dynamic places where special things can happen. For an electron moving from one material toward the other, this space is where it can join other electrons, which together can create current, magnetism or even light. Researchers have made fundamental discoveries at the border regions, called interfaces, between oxide materials.

Researchers have discovered how to manipulate electrons in oxide interfaces by inserting a single layer of atoms.
Credit: iStockphoto/Martin McCarthy

Most people cross borders such as doorways or state lines without thinking much about it. Yet not all borders are places of limbo intended only for crossing. Some borders, like those between two materials that are brought together, are dynamic places where special things can happen.

For an electron moving from one material toward the other, this space is where it can join other electrons, which together can create current, magnetism or even light.

A multi-institutional team has made fundamental discoveries at the border regions, called interfaces, between oxide materials. Led by University of Wisconsin-Madison materials science and engineering professor Chang-Beom Eom, the team has discovered how to manipulate electrons in oxide interfaces by inserting a single layer of atoms. The researchers also have discovered unusual electron behaviors at these engineered interfaces.

Their work, which is sponsored by the National Science Foundation, is published Feb. 18 in the journal Science and could allow researchers to further study and develop interfaces with a wide array of properties.

Eom's team blends theorists and experimentalists, including UW-Madison physics professor Mark Rzchowski and collaborators at the University of Nebraska-Lincoln, University of Michigan, Argonne National Laboratory and Brookhaven National Laboratory.

The researchers used two pieces of precisely grown strontium titanate, which is a type of oxide, or compound with oxygen as a fundamental element. Between the pieces, the researchers inserted a one-atom-thick layer of one of five rare-earth elements, which are important components in the electronics industry.

The team found that the rare-earth element layer creates an electron gas that has some interesting characteristics. The gas actually behaves more like an electron "liquid," since the electrons move more in tandem, or in correlation, than a gas normally does.

"If you take two materials, each has different characteristics, and if you put them together, at their interface you may find something unexpected," Eom says.

This research is the first demonstration of strong correlation among electrons at an oxide interface. The electron layer displayed distinct characteristics depending on the particular rare-earth element the team used. Materials with larger ionic radii, such as lanthanum, neodymium and praseodymium, are conducting, whereas materials with smaller radii, including samarium and yttrium, are insulating.

The insulating elements form an electron gas that can be compared to a thick liquid, somewhat like honey. The higher viscosity (basically, thickness) means the electrons can't move around as freely, making them more insulating. Conversely, the conducting elements form a gas that is a "liquid" more like gasoline; the viscosity is lower, so the electrons can move more freely and are better conductors.

Prior to this research, scientists knew extra electrons could reside at interfaces, but they didn't realize the complexity of how the electrons then behaved together at those interfaces.

The discovery of liquid-like behavior in the electron layer could open up an entire field of interfacial engineering for other scientists to explore, as well as new applications that take advantage of electron interactions. Since Eom and his colleagues developed an understanding of the basic physics behind these behaviors, their work could be expanded to create not only conductive or insulating interfaces, but also magnetic or optical ones.

Though scientists previously have looked at semiconductor interfaces, Eom's team is the first to specifically address those that use oxide interfaces to control conducting states with a single atomic layer. Oxides make up a class of materials including millions of compounds, and each has its own unique set of properties. The ability to manipulate various oxide interfaces could give rise to new generations of materials, electronics and other devices.

"This advancement could make a broad impact in fields even beyond physics, materials or chemistry," Eom says. "People can use the idea that an interface made from a single atomic layer of different ions can be used to create all kinds of properties."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. W. Jang, D. A. Felker, C. W. Bark, Y. Wang, M. K. Niranjan, C. T. Nelson, Y. Zhang, D. Su, C. M. Folkman, S. H. Baek, S. Lee, K. Janicka, Y. Zhu, X. Q. Pan, D. D. Fong, E. Y. Tsymbal, M. S. Rzchowski, C. B. Eom. Metallic and Insulating Oxide Interfaces Controlled by Electronic Correlations. Science, 2011; 331 (6019): 886 DOI: 10.1126/science.1198781

Cite This Page:

University of Wisconsin-Madison. "Engineering atomic interfaces for new electronics." ScienceDaily. ScienceDaily, 22 February 2011. <www.sciencedaily.com/releases/2011/02/110217141317.htm>.
University of Wisconsin-Madison. (2011, February 22). Engineering atomic interfaces for new electronics. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2011/02/110217141317.htm
University of Wisconsin-Madison. "Engineering atomic interfaces for new electronics." ScienceDaily. www.sciencedaily.com/releases/2011/02/110217141317.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins