Synchrotrons help bring superconductors out of the cold

The longstanding search for a room temperature superconductor is fueled by a tantalizing set of possible applications that sound like science fiction: infinitely long power lines that never lose energy, magnetically levitating trains, and incredibly fast quantum computers.

Superconductors have zero resistance, the electric equivalent to friction, when cooled below a specified temperature. The temperatures involved are alarmingly low, ranging from a couple of degrees above absolute zero to a balmy -135°C, still too cold for large scale practical use. Advances in high temperature superconductor research have been slow in part because their physics is poorly understood.

Now an international team of researchers has made a major breakthrough in understanding the limits of these materials. The collaboration, including researchers from the Canadian Light Source, University of Waterloo, and the University of British Columbia, used no less than four synchrotron facilities worldwide in order to confirm their results.

 A synchrotron, like Saskatoon’s CLS, where some of the experiments were performed, is a football-field-sized source of brilliant light that enables scientists to study the microstructure and chemical properties of materials

The team found the first experimental evidence that a so-called “charge-density-wave instability” competes with superconductivity. Armed with this knowledge, scientists can start to design new materials that will bring superconductors out of the cold and into large-scale real world applications.

“Without very specific evidence it is like theorists are shooting in the dark. Our new data will narrow their target significantly” explained Canadian Light Source scientist Dr. Feizhou He.

The collaboration, led by Dr. Giacomo Ghiringhelli of CNR-SPIN and the Milan Polytechnic University included the work of several prominent institutions, including  the Max Planck Institute for Solid State Physics , European Synchrotron Radiation Facility (ESRF) and the Helmholtz Centre Berlin along with the three Canadian institutes. Data was collected at the ADRESS beamline of the Swiss Light Source, the ID08 Dragon beamline at ESRF, UE46-PGM1 at Bessy-II and REIXS at the CLS. The results were published this week in the prestigious American journal Science.

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The Canadian Light Source is Canada’s national centre for synchrotron research. Located in Saskatoon, the CLS is a powerful tool for academic and industrial research in a wide variety of areas including environmental science, natural resources and energy, health and life sciences, and information and communications technology. CLS operations are funded by the Western Economic Diversification Canada, Natural Science and Engineering Research Council, National Research Council of Canada, Canadian Institutes of Health Research, the Government of Saskatchewan and the University of Saskatchewan. For more information: www.lightsource.ca/media/quickfacts.php.

The full paper is available at http://www.sciencemag.org/content/early/2012/07/11/science.1223532