From Brookhaven Lab: “Atomic-scale Visualization of Electron Pairing in Iron Superconductors”

Brookhaven National Laboratory

Findings support magnetic pairing theory that could lead to new improved superconductors

May 3, 2012
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“By measuring how strongly electrons are bound together to form Cooper pairs in an iron-based superconductor, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, Cornell University, St. Andrews University, and collaborators provide direct evidence supporting theories in which magnetism holds the key to this material’s ability to carry current with no resistance. Because the measurements take into account the electronic bands and directions in which the electrons are traveling, which was central to testing the theoretical predictions, this research strengthens confidence that this type of theory may one day be used to identify or design new materials with improved properties — namely, superconductors operating at temperatures far higher than today’s. The findings are published in the May 4, 2012 issue of Science.”

Data supports role of magnetism in iron-based superconductors: The height of each dot in this image represents the superconducting energy gap — a measure of the strength of electron pairing — for electrons moving at a particular momentum (speed in a given direction) on each electronic band (red and yellow rings) of a particular iron superconductor. The data show that the magnitude of the gap (height of the dots) varies by its momentum (position along the base plane) and the band it is on — which is exactly what was predicted by theories in which magnetism plays a primary role in the emergence of superconductivity. The results therefore strengthen confidence that those theories may help scientists discover or design new superconductors.

‘In the best possible world you would be able to take this theory and plug in different chemical elements until you find a combination that should work as a superconductor at higher temperatures,’ said team leader Séamus Davis, Director of the Center for Emergent Superconductivity at Brookhaven and the J.G. White Distinguished Professor of Physical Sciences at Cornell University. Such materials could be used for real world, energy-saving technologies, such as zero-loss power transmission lines, without the need for expensive coolants.”

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One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.