Featured Research

from universities, journals, and other organizations

You can't play nano-billiards on a bumpy table

Date:
May 14, 2012
Source:
University of New South Wales
Summary:
There's nothing worse than a shonky pool table with an unseen groove or bump that sends your shot off course: a new study has found that the same goes at the nano-scale, where the "billiard balls" are tiny electrons moving across a "table" made of the semiconductor gallium arsenide. Physicists have shown that in this game of "semiconductor billiards," small bumps have an unexpectedly large effect on the paths that electrons follow.

Lab scene (from left): UNSW lead author Dr Andrew See, with University of Oregon students Ian Pilgrim and Rick Montgomery.
Credit: Image courtesy of University of New South Wales

There's nothing worse than a shonky pool table with an unseen groove or bump that sends your shot off course: a new study has found that the same goes at the nano-scale, where the "billiard balls" are tiny electrons moving across a "table" made of the semiconductor gallium arsenide.

These tiny billiard tables are of interest towards the development of future computing technologies. In a research paper titled "The Impact of Small-Angle Scattering on Ballistic Transport in Quantum Dots," an international team of physicists has shown that in this game of "semiconductor billiards," small bumps have an unexpectedly large effect on the paths that electrons follow.

Better still, the team has come up with a major redesign that allows these bumps to be ironed out. The study, led by researchers from the UNSW School of Physics, is published in the journal Physical Review Letters.

The team included colleagues, from the University of Oregon (US), Niels Bohr Institute (Denmark) and Cambridge University (UK).

"Scaled down a million-fold from the local bar variety, these microscopic pool tables are cooled to just above absolute zero to study fundamental science, for example, how classical chaos theory works in the quantum mechanical limit, as well as questions with useful application, such as how the wave-like nature of the electron affects how transistors work," says team member Associate Professor Adam Micolich. "In doing this, impurities and defects in the semiconductor present a serious challenge."

Ultra-clean materials are used to eliminate impurities causing backscattering (akin to leaving a glass on the billiard table) but until now has been no way to avoid the ionized silicon atoms that supply the electrons.

"Their electrostatic effect is more subtle, essentially warping the table's surface." explains Micolich.

Earlier studies assumed this warping was negligible, with the electron paths determined only by the billiard table's shape (e.g. square, circular, stadium-shaped).

"We found that we can 'reconfigure' the warping by warming the table up and cooling it down again, with the electron paths changing radically in response," says Professor Richard Taylor from the University of Oregon. "This shows that the warping is much more important than expected."

Using a new billiard design developed during PhD work at UNSW by lead author Dr Andrew See, the silicon dopants are removed, eliminating the associated warping, and enabling the electron paths to stay the same each time they cool the device down for study.

"These undoped billiard devices pinpoint the silicon dopants as the cause of the warping. The level of improvement obtained by removing the silicon was unexpected, earlier work on much larger devices suggested that we wouldn't see this level of improvement.

But at the nanoscale, the dopant atoms really do make a really big difference," says Micolich, "Ultimately, our work provides important insight into how to make better nanoscale electronic devices, ones where the properties are both more predictable, and more consistent each time we use them."


Story Source:

The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. See, I. Pilgrim, B. Scannell, R. Montgomery, O. Klochan, A. Burke, M. Aagesen, P. Lindelof, I. Farrer, D. Ritchie, R. Taylor, A. Hamilton, A. Micolich. Impact of Small-Angle Scattering on Ballistic Transport in Quantum Dots. Physical Review Letters, 2012; 108 (19) DOI: 10.1103/PhysRevLett.108.196807

Cite This Page:

University of New South Wales. "You can't play nano-billiards on a bumpy table." ScienceDaily. ScienceDaily, 14 May 2012. <www.sciencedaily.com/releases/2012/05/120514104957.htm>.
University of New South Wales. (2012, May 14). You can't play nano-billiards on a bumpy table. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/05/120514104957.htm
University of New South Wales. "You can't play nano-billiards on a bumpy table." ScienceDaily. www.sciencedaily.com/releases/2012/05/120514104957.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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