Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ORNL paper examines clues for superconductivity in an iron-based material

06.05.2014

For the first time, scientists have a clearer understanding of how to control the appearance of a superconducting phase in a material, adding crucial fundamental knowledge and perhaps setting the stage for advances in the field of superconductivity.


A change of Hall and Seebeck effects point to large Fermi surface modification at the structural transition, preventing superconductivity at low temperatures. The change in the Fermi surface topology has been confirmed by angle-resolved photoemission spectroscopy.

The paper, published in Physical Review Letters, focuses on a calcium-iron-arsenide single crystal, which has structural, thermodynamic and transport properties that can be varied through carefully controlled synthesis, similar to the application of pressure. To make this discovery, researchers focused on how these changes alter the material’s Fermi surface, which maps the specific population and arrangement of electrons in materials.

“The Fermi surface is basically the ‘genetic code’ for causing a certain property, including superconductivity, in a material,” said Athena Safa-Sefat of the Department of Energy’s Oak Ridge National Laboratory, which led the research team.

“We can make different phases of this material in single crystal forms and measure their structure and properties, but now we have Fermi surface signatures that explain why we can't induce superconductivity in a certain structural phase of this material.”

Superconducting wires conduct electricity without resistance and could save the nation billions of dollars per year by virtually eliminating transmission losses on the grid, or they can be used to make compact, light and powerful motors and generators. This particular material is of special interest because it adds critical knowledge to the field of superconductivity that will ultimately allow such widespread applications.

The lead author of this paper, Krzysztof Gofryk, who did this work as a post-doctoral fellow at ORNL, showed how the interplay of structure and magnetism affected the Fermi surface and hence the electronic properties.

In calcium-iron-arsenide, the bulk superconducting state is absent because of the large Fermi surface modification at the structural transition.

This work represents a significant step forward for understanding this material's rich phase diagram and causes of superconductivity, Sefat said.
 
Other authors of the paper, titled “Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe2As2,” are ORNL’s post-doctoral fellow Bayrammurad Saparov and scientists from Los Alamos National Laboratory and Dresden University of Technology. The paper is available at http://arxiv.org/abs/1404.1095.

This research was funded by DOE’s Office of Science and by LANL’s Laboratory Directed Research and Development program.

UT-Battelle manages ORNL for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of the time. For more information, please visit href="http://arxiv.org/abs/1404.1095".

Ron Walli | Eurek Alert!

Further reports about: Fermi Laboratory ORNL Office Superconducting pressure transition

More articles from Materials Sciences:

nachricht “Reverse Engineering” Materials for More Efficient Heating and Cooling
29.10.2014 | American Institute of Physics (AIP)

nachricht Watching the hidden life of materials
28.10.2014 | McGill University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Anzeige

Anzeige

Event News

Registration Open Now: 18th International ESAFORM Conference on Material Forming

28.10.2014 | Event News

Comparing Apples and Oranges? A Colloquium on International Comparative Urban Research

22.10.2014 | Event News

Battery Conference April 2015 in Aachen

16.10.2014 | Event News

 
Latest News

Sculpting solar systems: Magnetic fields seen for first time

31.10.2014 | Physics and Astronomy

Here's Looking At You: Spooky Shadow Play Gives Jupiter a Giant Eye

31.10.2014 | Physics and Astronomy

New research reveals fish are smarter than we thought

31.10.2014 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>