“Strange metal,” that rogue phenomenon of the electrical realm, just became a little less enigmatic.
Identified more than 40 years ago, strange metal is a state of matter found in many quantum materials — including certain superconductors that scientists say may be vital for high-tech products of the future. The “strange” part of strange metal is its electrons: they defy the traditional rules for electron movement and conductivity.
Unlike most metals, in which electrical resistance increases with the square of temperature, strange metals have an electrical resistance that increases in proportion to temperature. This “linear-in-temperature” behavior defies physicists’ understanding of how electrons move in solids.
“This strange metal behavior is seen in many different materials, where at first glance, you wouldn’t think there is anything that ties them together,” said Eduardo H. da Silva Neto, an assistant professor of physics in Yale’s Faculty of Arts and Sciences and corresponding author of a new study in the journal Science Advances. “Most of the previous work investigating the strange metal phenomenon has focused on its ‘symptoms’ — its linear temperature resistance, for instance — rather than directly measuring the exact movement between electrons.”
There is no established theory for the strange metal phenomenon, da Silva Neto said, but most researchers believe that the linear-in-temperature behavior results from electrons that must be able to scatter in all directions. However, in the study, da Silva Neto and his colleagues found a discernable, circular scattering pattern in the way electrons move within strange metal.
The new study is an extension of da Silva Neto’s earlier work examining electron interactions in copper oxides. In that work, he and his colleagues discovered a similar circular pattern. Using a method called resonant inelastic X-ray scattering (RIXS), they saw that electrons created fluctuating waves of electrical charge in all directions.
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