The Kondo effect described the scattering of conduction electrons in a metal due to magnetic impurities, resulting in a characteristic change in electrical resistivity with temperature.
By now, all known cases of the effect are based on conduction electrons and are thus limited to electrical conductors, while it has been believed that the presence of conduction electrons is the key condition for the effect.
Recently, Slovenian physicists from the IJS, headed by Andrej Zorko, and their colleagues from Switzerland and China, were able to confirm the existence of the Kondo effect in a quantum spin liquid, which is actually an electrical insulator.
The discovery, made in an accelerator at the Paul Scherrer Institute in Switzerland, was recently reported on in the monthly scientific journal Nature Physics, the IJS announced on Tuesday.
The effect has been discovered in a quantum spin liquid, where frustrated magnetic moments, which do not carry electric charge, take over the role of conduction electrons in a metal.
The Kondo effect has become one of the most studied phenomenons in solid matter physics, as it enables the understanding of unusual electrical properties of a wide range of materials, from high-temperature superconductors to quantum dots and topological insulators.
The discovery of the effect in a quantum spin liquid is important both from the theoretical and technological aspect, as this quantum state represents a promising platform for high-performance quantum computers.
Effective manipulation of this state is what is currently the biggest challenge, the Slovenian institute said.
In the article, Slovenian researchers propose that the required control of the state of a quantum spin liquid could be achieved by manipulation of impurities, and that the Kondo effect could serve as a connection between the state of impurity and the state of quantum spin liquid.