Scientists May Have Decoded One of the Secrets to Superconductors | Science | WIRED - 0 views
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“In the same way that a laser is a hell of a lot more powerful than a light bulb, room-temperature superconductivity would completely change how you transport electricity and enable new ways of using electricity,” said Louis Taillefer, a professor of physics at the University of Sherbrooke in Quebec.
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ripples of electrons inside the superconductors that are called charge density waves. The fine-grained structure of the waves, reported in two new papers by independent groups of researchers, suggests that they may be driven by the same force as superconductivity. Davis and his colleagues directly visualized the waves in a study posted online in April, corroborating indirect evidence reported in February by a team led by Riccardo Comin, a postdoctoral fellow at the University of Toronto.
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Taken together, the various findings are at last starting to build a comprehensive picture of the physics behind high-temperature superconductivity. “This is the first time I feel like we’re making real progress,” said Andrea Damascelli, a professor of physics at the University of British Columbia who led two recent studies on charge density waves. “A lot of different observations which have been made over decades did not make sense with each other, and now they do.”
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The community remained divided until 2012, when two groups using a technique called resonant X-ray scattering managed to detect charge density waves deep inside cuprates, cementing the importance of the waves. As the groups published their findings in Science and Nature Physics, two new collaborations formed, one led by Damascelli and the other by Ali Yazdani of Princeton University, with plans to characterize the waves even more thoroughly. Finishing in a dead heat, the rival groups’ independent studies appeared together in Science in January 2014. They confirmed that charge density waves are a ubiquitous phenomenon in cuprates and that they strenuously oppose superconductivity, prevailing as the temperature rises.
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y applying Sachdev’s algorithm to a new round of data, Davis and his group mapped out the structure of the charge density waves, showing that the d-wave distribution of electrons was, indeed, their source.
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The waves’ structure is particularly suggestive, researchers say, because superconducting pairs of electrons also have a d-wave configuration. It’s as if both arrangements of electrons were cast from the same mold. “Until a few months ago my thought was, OK, you have charge density waves, who cares? What’s the relevance to the high-temperature superconductivity?” Damascelli said. “This tells me these phenomena feed off the same interaction.”
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In short, antiferromagnetism could generate the d-wave patterns of both superconductivity and its rival, charge density waves.