May 31, 2007
A team of University of British Columbia researchers has contributed to the greatest advancement in superconductor research in a decade by "growing" the purest samples of superconductors to date.
Superconductors are a class of materials that conduct electricity with no resistance. They are already used in MRI medical imaging scanners, levitating trains, and power lines. High temperature superconductors have no resistance at temperatures as high as -140 degrees Celsius, but advances in this area have been stalled due to a lack of understanding of their fundamental properties.
"Up to now, it was unclear whether these materials were metals or insulators," said UBC Physics Prof. Douglas Bonn, adding that the materials are extremely sensitive to contamination - the slightest trace of dirt or impurity can alter their properties completely.
"We were able to supply our collaborators with the purest sample ever developed, leading to the discovery of quantum oscillations," said Bonn. "This provides unequivocal proof that these materials are metals."
"The results are crystal clear," said Louis Taillefer. "High-temperature superconductors were discovered in 1987, and only now do we finally have concrete knowledge about their deep nature. This discovery gives both theorists and experimentalists something real to work with."
Despite their name, high-temperature superconductors cannot function in temperatures higher than 100 degrees Celsius below zero. The discovery brings scientists one step closer to the ultimate goal of creating room-temperature superconductors, which could result in laptop-sized MRI machines, loss-less power lines, and vast improvements in computers and wireless communications.
The UBC team also includes Prof. Emeritus Walter Hardy and Materials Scientist Ruixing Liang. Findings of the project, led by Université de Sherbrooke physicist Louis Taillefer and involving researchers and funding from the Canadian Institute for Advanced Research (CIFAR), are published in the journal Nature. The experiments were carried out at the National Pulsed Magnetic Field Laboratory in Toulouse, France.