Kondo screening in a charge-insulating spinon metal

Gomilšek, M.; Žitko, R.; Klanjšek, M.; Pregelj, M.; Baines, C.; Li, Y.; Zhang, Q.M.; Zorko, A.

Abstract

The Kondo effect, an eminent manifestation of many-body physics in condensed matter, is traditionally explained as exchange scattering of conduction electrons on a spinful impurity in a metal1,2. The resulting screening of the impurity’s local moment by the electron Fermi sea is characterized by a Kondo temperature TK, below which the system enters a strongly coupled regime. In recent years, this effect has found realizations beyond the bulk-metal paradigm in many other conduction-electron systems, such as in quantum dots in semiconductor heterostructures3,4 and nanomaterials5,6,7, in quantum point contacts8,9, in graphene10,11 and in topological insulators12, and has also been predicted for three-dimensional Dirac and Weyl semimetals13. Here, we report an experimental observation of Kondo screening by charge-neutral quasiparticles. This occurs in a charge-insulating quantum spin liquid, where spinon excitations forming a Fermi surface take the role of conduction electrons. The observed impurity behaviour therefore bears a strong resemblance to the conventional case in a metal. The discovered spinon-based Kondo effect provides a prominent platform for characterizing spin liquids in the general context of utilizing impurities as in situ probes of host electron states14,15, and offers a unique way to manipulate these enigmatic states.

Citation

Gomilšek, M., Žitko, R., Klanjšek, M., Pregelj, M., Baines, C., Li, Y., Zhang, Q., & Zorko, A. (2019). Kondo screening in a charge-insulating spinon metal. Nature Physics, 15(8), 754-758. https://doi.org/10.1038/s41567-019-0536-2

• Journal Article Type: Article
• Acceptance Date: Apr 12, 2019
• Online Publication Date: May 27, 2019
• Publication Date: Aug 1, 2019
• Deposit Date: May 31, 2019
• Publicly Available Date: Nov 27, 2019
• Journal: Nature Physics
• Print ISSN: 1745-2473
• Electronic ISSN: 1745-2481
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 15
• Issue: 8
• Pages: 754-758
• DOI: https://doi.org/10.1038/s41567-019-0536-2
• Public URL: https://durham-repository.worktribe.com/output/1300250
• Related Public URLs: https://arxiv.org/abs/1904.06506