Science 101: Superconductivity
Superconductivity is the absence of electrical resistance in a material that has been cooled to a very low temperature. Because electrical current can travel with no resistance, superconductors hold the promise of improving electrical transmission, being used for powerful electromagnets in levitation trains or medical imagers, and giving rise to faster and more efficient computer components.
To unlock this potential, researchers in CIFAR’s program in Quantum Materials are investigating the many unusual properties superconductors exhibit, with one major goal being to develop superconductors that operate at higher temperatures. Superconductivity occurs due to a quantum effect that allows electrons to form pairs called Cooper pairs.
This pairing imposes order on the system and allows the electrons to flow without resistance. But other properties of a material can compete against superconductivity, including magnetism and a phenomenon called charge order.
CIFAR researchers are making advances in understanding these and other effects. Although most superconductors require temperatures below 30 degrees Kelvin, materials have been discovered recently that remain superconductors at much higher critical temperatures. These include materials like copper oxides (or “cuprates”) and iron arsenides (or “pnictides”), and others. The advantage of high-temperature superconductors is that they can be cooled with inexpensive liquid nitrogen, with a boiling point of 77 K, rather than more expensive liquid helium, with a boiling point of 4.2 K. Eventually, research could lead to a truly room-temperature superconductor. Louis Taillefer, the director of CIFAR’s Quantum Materials program, predicts that room-temperature superconductors would spark a technological revolution similar to that of the invention of the laser, which today plays a role in an estimated $7.5 trillion in economic activity.
Image above: A model showing part of the crystal structure of copper oxide, a superconducting material.
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