Featured Research

from universities, journals, and other organizations

Superconducting Chips To Become Reality

Date:
May 29, 2009
Source:
Forschungszentrum Dresden Rossendorf
Summary:
Most chemical elements become superconducting at low temperatures or high pressures, but until now, copper, silver, gold, and the semiconductor germanium, for example, have all refused superconductivity. Scientists have now able to produce superconducting germanium for the first time. Furthermore, they could unravel a few of the mysteries which come along with superconducting semiconductors.

Artist view of the implantation of gallium ions (animated in blue) into germanium wafers followed by a reconstruction of the lattice using short-term flash-lamp annealing and, finally, of the observation of superconductivity at low temperatures. Other than in normal conductors, superconductivity is caused by the formation of electron pairs with anti-parallel momentum and spin (animated in red).
Credit: Sander Münster, Kunstkosmos

Most chemical elements become superconducting at low temperatures or high pressures, but until now, copper, silver, gold, and the semiconductor germanium, for example, have all refused superconductivity. Scientists at the Forschungszentrum Dresden-Rossendorf (FZD) research center were now able to produce superconducting germanium for the first time. Furthermore, they could unravel a few of the mysteries which come along with superconducting semiconductors.

Superconductors are substances that conduct electricity without losses when cooled down to very low temperatures. Pure semiconductors, like silicon or germanium, are almost non-conducting at low temperatures, but transform into conducting materials after doping with foreign atoms. An established method of doping is ion implantation (ions = charged atoms) by which foreign ions are embedded into the crystal lattice of a semiconductor. To produce a superconducting semiconductor, an extreme amount of foreign atoms are necessary, even more than the substance would usually be able to absorb. At the FZD, germanium samples were doped with about six gallium atoms per 100 germanium atoms. With these experiments, the scientists could prove indeed that the doped germanium layer of only sixty nanometers thickness became superconducting, and not just the clusters of foreign atoms which could easily form during extreme doping .

As the germanium lattice is heavily damaged by ion implantation, it has to be repaired afterwards. For such purposes, a flash-lamp annealing facility has been developed at the FZD. Its application allows for a repair of the destroyed crystal lattice by rapidly heating the sample surface (within few milliseconds) while the distribution of the dopant atoms is kept almost the same.

From a scientific point of view, the new material is very promising. It exhibits a surprisingly high critical magnetic field with respect to the temperature where the substance becomes superconducting. For many materials, superconductivity occurs only at very low temperatures, slightly above the absolute zero point of -273 degrees Celsius or 0 Kelvin. The gallium doped germanium samples become superconducting at about 0.5 Kelvin; however, the FZD researchers expect the temperature to increase further by changing various parameters during ion implantation or annealing.

Physicists have been dreaming about superconducting semiconductors for a long time, but saw only few chances for the semiconductor germanium to become superconducting at all. Germanium used to be the material for the first generation of transistors; however, it was soon replaced by silicon, the current material for microelectronics. Recently, the “old” semiconductor material germanium has aroused more and more interest, as it allows, compared to silicon, for more rapid circuits.

Experts even believe germanium to be rediscovered for micro- and nanoelectronics. The reason for such a renaissance lies in the fact that miniaturization in microelectronics industry using silicon is coming to an end. Today, extremely thin oxide layers are needed for transistors, down to a level where silicon oxide does not work well any more. Germanium as a new material for chips would come along with two big advantages: it would enable both faster processes and further miniaturization in micro- and nanoelectronics. Superconducting germanium could thus help to realize circuits for novel computers.

The scientists at the Forschungszentrum Dresden-Rossendorf followed a targeted approach when searching for a new superconducting semiconductor. Instead of doping with boron, which had resulted in superconducting silicon two years ago in France, the scientists choose gallium because of its higher solubility in germanium. In many systematic experiments they proved that the superconductivity of germanium can be reproduced. Furthermore, they were able to show that the transition temperature marking the start of superconductivity can be raised within certain limits.

In the future, the scientists at the two FZD institutes “Ion Beam Physics and Materials Research” and “Dresden High Magnetic Field Laboratory” will combine their know-how in order to fine-tune different rather complex parameters for further experiments, thus hopefully discovering further mysteries of superconducting semiconductors.


Story Source:

The above story is based on materials provided by Forschungszentrum Dresden Rossendorf. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Herrmannsdörfer, V. Heera, O. Ignatchik, M. Uhlarz, A. Mücklich, M. Posselt, H. Reuther, B. Schmidt, K.-H. Heinig, W. Skorupa, M. Voelskow, C. Wündisch, R. Skrotzki, M. Helm, J. Wosnitza. Superconducting state in a gallium-doped germanium layer at low temperatures. Physical Review Letters, Volume 102, Number 21, page 217003 (2009) DOI: 10.1103/PhysRevLett.102.217003

Cite This Page:

Forschungszentrum Dresden Rossendorf. "Superconducting Chips To Become Reality." ScienceDaily. ScienceDaily, 29 May 2009. <www.sciencedaily.com/releases/2009/05/090528092520.htm>.
Forschungszentrum Dresden Rossendorf. (2009, May 29). Superconducting Chips To Become Reality. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2009/05/090528092520.htm
Forschungszentrum Dresden Rossendorf. "Superconducting Chips To Become Reality." ScienceDaily. www.sciencedaily.com/releases/2009/05/090528092520.htm (accessed September 1, 2014).

Share This




More Matter & Energy News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) — Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) — Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) — Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) — An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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