The current-carrying ability of so-called strange metals defies the known rules of electricity. Now Aavishkar Patel of the Flatiron Institute, New York, and his colleagues have an explanation for why [1]. They say that the result could help scientists find new materials that exhibit high-temperature superconductivity, of which strange metallicity is a precursor state.
If you heat a slab of copper, its electrical resistance—how much the material opposes the flow of an electrical current—will increase with the square of the temperature. But if you add some oxygen, lanthanum, and barium to that copper, the behavior suddenly changes. The resulting cuprate material has no electrical resistance at very low temperatures, but as it gets hotter the resistance increases linearly with temperature, making it a poorer conductor than a normal metal like copper. Other properties of the material are also abnormal, including its ability to absorb heat and to transport a rapidly oscillating electrical current. “But the resistivity change is the most striking,” Patel says.
Scientists first uncovered these resistance oddities in 1986, but they have struggled to explain their origin. Last year, experiments confirmed a theory explaining the zero-resistance behavior (superconductivity) in cuprates. Now theorists have an explanation for the linear-resistance trend (strange metallicity) observed in cuprates and in other materials (see Viewpoint: Graphene Reveals Its Strange Side).
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