Wu group discovered a new mode of electron conduction in solids: decoupled charge and heat transport.

Berkeley Lab scientists Junqiao Wu, Fan Yang, and Changhyun Ko (l-r) are working at the nano-Auger electron spectroscopy instrument at the Molecular Foundry, a DOE Office of Science User Facility. They used the instrument to determine the amount of tungsten in the tungsten-vanadium dioxide (WVO2) nanobeams. (Credit: Marilyn Chung/Berkeley Lab)

by Daisy Hernandez

January 26, 2017

In metals, electrons carry both charge and heat. As a consequence, electrical conductivity and the electronic contribution to the thermal conductivity are typically proportional to each other. Prof. Junqiao Wu's group and collaborators found a large violation of this so-called Wiedemann-Franz law near the insulator-metal transition in VO2 nanobeams. In the metallic phase, the electronic contribution to thermal conductivity was much smaller than what would be expected from the Wiedemann-Franz law. The results can be explained in terms of independent propagation of charge and heat in a strongly correlated system. The work is published in Science, Vol. 355, Issue 6323, pp. 371-374 (2017). Read more here!

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