Many people picture electrical conductivity as the flow of charged particles (mainly electrons) without really thinking about the atomic structure of the material through which those charges are moving. But scientists who study "strongly correlated electron" materials such as high-temperature superconductors and those with strong responses to magnetism know that picture is far too simplistic. They know that the atoms play a crucial role in determining a material's properties.
For example, electrical resistance is a manifestation of electrons scattering off the atoms. Less evident is the concept that electrons and atoms can move cooperatively to stop the flow of charge -- or, in the other extreme, make electrons flow freely without resistance.
Now, a team led by physicist Yimei Zhu at the U.S. Department of Energy's Brookhaven National Laboratory has produced definitive evidence that the movement of electrons has a direct effect on atomic arrangements, driving deformations in a material's 3D crystalline lattice in ways that can drastically alter the flow of current. Finding evidence for these strong electron-lattice interactions, known as polarons, emphasizes the need to quantify their impact on complex phenomena such as superconductivity (the ability of some materials to carry current with no energy loss) and other promising properties.
As described in a paper just published in the Nature partner journal npj Quantum Materials, the team developed an "ultrafast electron diffraction" system -- a new laser-driven imaging technique and the first of its kind in the world -- to capture the subtle atomic-scale lattice distortions. The method has widespread potential application for studying other dynamic processes.
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