Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hidden order found in cuprates may help explain superconductivity

13.02.2004


Like the delicate form of an icicle defying gravity during a spring thaw, patterns emerge in nature when forces compete. Scientists at the University of Illinois at Urbana-Champaign have found a hidden pattern in cuprate (copper-containing) superconductors that may help explain high-temperature superconductivity.




Superconductivity, the complete loss of electrical resistance in some materials, occurs at temperatures near absolute zero. First observed in 1911 by Dutch physicist Heike Kamerlingh Onnes, the mechanism of superconductivity remained unexplained until 1957, when Illinois physicists John Bardeen, Leon Cooper, and J. Robert Schrieffer determined that electrons, normally repulsive, could form pairs and move in concert in superconducting materials below a certain critical temperature.

For more than a decade, scientists have been baffled by superconductivity in the copper oxides, which occurs at liquid-nitrogen temperatures and does not seem to behave according to standard BCS theory. A tantalizing goal, which would have enormous implications for electronics and power distribution, is to achieve superconductivity at room temperature. A large piece of the puzzle has been to understand how the coherent dance of electrons that gives rise to superconductivity changes when the material is heated.


In a paper to appear in the journal Science, as part of the Science Express Web site, on Feb. 12, researchers at Illinois show that when heated, the orderly superconducting dance of electrons is replaced, not by randomness as might be assumed, but by a distinct type of movement in which electrons organize into a checkerboard pattern. The experimental findings imply that the two types of electron organization, coherent motion and spatial organization, are in competition in the copper oxides -- an idea that may break the logjam on the mystery of high-temperature superconductivity.

"Heating a normal superconductor above its critical temperature results in a normal metallic behavior, but heating a high-temperature superconductor above its critical temperature results in a non-metallic state of electrons called the pseudogap state," said physics professor Ali Yazdani, a Willett Faculty Scholar at Illinois and senior author of the paper. "We have examined for the first time the motion of electrons in this mysterious pseudogap state on the nanometer scale."

Yazdani and graduate students Michael Vershinin and Shashank Misra used a scanning tunneling microscope to map electron waves in cuprate superconductors at high temperatures.

"Comparing maps of electron waves in both the superconducting and the pseudogap state, we have found that electrons in the pseudogap state organize into a checkerboard pattern," Yazdani said. "This pattern appears to be the result of competing forces felt by the electrons, such as Coulomb repulsion because of their charge and magnetic interactions resulting from their spins."

Regardless of the specific cause of the local ordering, "our experimental observations provide new constraints on the potential theoretical description of the pseudogap state in the cuprates and how it transforms into superconductivity when we cool the cuprate samples," Yazdani said.

Pattern formation of electron waves in high-temperature copper-oxide superconductors has long been anticipated theoretically, and Illinois physics professor Eduardo Fradkin contributed to the theoretical work. However, the experimental discovery of such pattern formation was made possible by a new generation of STM designed by Yazdani’s group to operate at temperatures above the superconducting transition temperature.

Collaborators on the pattern-formation project also included colleagues at the Central Research Institute of Electric Power Industry in Japan.


The National Science Foundation, Office of Naval Research and the U.S. Department of Energy funded the work.

James E. Kloeppel | UIUC

More articles from Physics and Astronomy:

nachricht Telescopes team up to study giant galaxy
12.12.2017 | International Centre for Radio Astronomy Research

nachricht Midwife and signpost for photons
11.12.2017 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

Liver Cancer: Lipid Synthesis Promotes Tumor Formation

12.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>