Uranium compound achieves record deviating Nernst conductivity

Science Advances has discovered that large spin-orbit coupling and strong electronic correlations in a uranium-cobalt-aluminum system doped with ruthenium resulted in colossal abnormal Nernst conductivity. Uranium and actinide alloys are promising materials to study the interactions between a material’s topology and strong electron correlations, which could one day have applications in quantum information technologies. Credit: Los Alamos National Laboratory “width =” 800 “height =” 530 “/>

New research has shown that a magnetic uranium compound can have strong thermoelectric properties, generating four times the transverse voltage of heat than the previous record in a cobalt-manganese-gallium compound. The result unlocks a new potential for the actinide elements at the bottom of the periodic table and points to a new direction in research into topological quantum materials.

“We found that the large spin-orbit coupling and strong electronic correlations in a uranium-cobalt-aluminum system doped with ruthenium resulted in a colossal abnormal Nernst conductivity,” said Filip Ronning, lead researcher of the paper published today in Science AdvancesRonning is director of the Institute for Materials Science at Los Alamos National Laboratory. “It illustrates that uranium and actinide alloys are promising materials to study the interplay between a material’s topology and strong electron correlations. We are very interested in understanding, tuning and ultimately controlling this interplay, so hopefully we can day to take advantage of some of these. remarkable reactions. “

The Nernst reaction occurs when a material converts a heat flow into an electrical voltage. This thermoelectric phenomenon can be exploited in devices that generate electricity from a heat source. The most notable current example is the radioisotope thermoelectric generators (RTGs) partially developed in Los Alamos. RTGs use heat from plutonium-238’s natural radioactive decay to generate electricity – one of those RTGs is currently powering the Perseverance rover on Mars.

“What’s exciting is that this colossal aberrant Nernst effect appears to be due to the rich topology of the material. This topology is created by a large spin-orbit coupling, which is common in actinides,” said Ronning. “One consequence of topology in metals is the generation of a transverse velocity, which can give rise to a Nernst response, as we see. It can also generate other effects, such as new surface states that may be useful in different quantum information technologies.”

The uranium system studied by the Los Alamos team generated 23 microvolts per kelvin of temperature change – four times greater than the previous record, discovered in a cobalt-manganese-gallium alloy a few years ago and also attributed to this kind of topological origin.