Featured Research

from universities, journals, and other organizations

Physicists pinpoint key property of material that both conducts and insulates

Date:
August 21, 2013
Source:
University of Washington
Summary:
Scientists have made the first-ever accurate determination of a solid-state triple point -- the temperature and pressure at which three different solid phases can coexist stably -- in a substance called vanadium dioxide.

The lines of data points are where two of the three solid-state phases of vanadium dioxide can exist stably together, and the point where the three lines meet -- the triple point -- is where all three phases can exist together.
Credit: David Cobden/University of Washington

It is well known to scientists that the three common phases of water -- ice, liquid and vapor -- can exist stably together only at a particular temperature and pressure, called the triple point.

Related Articles


Also well known is that the solid form of many materials can have numerous phases, but it is difficult to pinpoint the temperature and pressure for the points at which three solid phases can coexist stably.

Scientists now have made the first-ever accurate determination of a solid-state triple point in a substance called vanadium dioxide, which is known for switching rapidly -- in as little as one 10-trillionth of a second -- from an electrical insulator to a conductor, and thus could be useful in various technologies.

"These solid-state triple points are fiendishly difficult to study, essentially because the different shapes of the solid phases makes it hard for them to match up happily at their interfaces," said David Cobden, a University of Washington physics professor.

"There are, in theory, many triple points hidden inside a solid, but they are very rarely probed."

Cobden is the lead author of a paper describing the work, published Aug. 22 in Nature.

In 1959, researchers at Bell Laboratories discovered vanadium dioxide's ability to rearrange electrons and shift from an insulator to a conductor, called a metal-insulator transition. Twenty years later it was discovered that there are two slightly different insulating phases.

The new research shows that those two insulating phases and the conducting phase in solid vanadium dioxide can coexist stably at 65 degrees Celsius, give or take a tenth of a degree (65 degrees C is equal to 149 degrees Fahrenheit).

To find that triple point, Cobden's team stretched vanadium dioxide nanowires under a microscope. The team had to build an apparatus to stretch the tiny wires without breaking them, and it was the stretching that allowed the observation of the triple point, Cobden said.

It turned out that when the material manifested its triple point, no force was being applied -- the wires were not being stretched or compressed.

The researchers originally set out simply to learn more about the phase transition and only gradually realized that the triple point was key to it, Cobden said. That process took several years, and then it took a couple more to design an experiment to pin down the triple point.

"No previous experiment was able to investigate the properties around the triple point," he said.

He regards the work as "just a step, but a significant step" in understanding the metal-insulator transition in vanadium dioxide. That could lead to development of new types of electrical and optical switches, Cobden said, and similar experiments could lead to breakthroughs with other materials.

"If you don't know the triple point, you don't know the basic facts about this phase transition," he said. "You will never be able to make use of the transition unless you understand it better."


Story Source:

The above story is based on materials provided by University of Washington. The original article was written by Vince Stricherz. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jae Hyung Park, Jim M. Coy, T. Serkan Kasirga, Chunming Huang, Zaiyao Fei, Scott Hunter, David H. Cobden. Measurement of a solid-state triple point at the metal–insulator transition in VO2. Nature, 2013; 500 (7463): 431 DOI: 10.1038/nature12425

Cite This Page:

University of Washington. "Physicists pinpoint key property of material that both conducts and insulates." ScienceDaily. ScienceDaily, 21 August 2013. <www.sciencedaily.com/releases/2013/08/130821132346.htm>.
University of Washington. (2013, August 21). Physicists pinpoint key property of material that both conducts and insulates. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/08/130821132346.htm
University of Washington. "Physicists pinpoint key property of material that both conducts and insulates." ScienceDaily. www.sciencedaily.com/releases/2013/08/130821132346.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Obama: Better Ways to Create Jobs Than Keystone Pipeline

Obama: Better Ways to Create Jobs Than Keystone Pipeline

AFP (Dec. 19, 2014) US President Barack Obama says that construction of the Keystone pipeline would have 'very little impact' on US gas prices and believes there are 'more direct ways' to create construction jobs. Duration: 00:47 Video provided by AFP
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