Evidence for a spinon Kondo effect in cobalt atoms on single-layer 1T-TaSe$_2$
Abstract
Quantum spin liquids (QSLs) are highly entangled, disordered magnetic states that arise in frustrated Mott insulators and host exotic fractional excitations such as spinons and chargons. Despite being charge insulators some QSLs are predicted to exhibit gapless itinerant spinons that yield metallic behavior in the spin channel. We have deposited isolated magnetic atoms onto single-layer (SL) 1T-TaSe, a gapless QSL candidate, to experimentally probe how itinerant spinons couple to impurity spin centers. Using scanning tunneling spectroscopy we observe the emergence of new, impurity-induced resonance peaks at the 1T-TaSe Hubbard band edges when cobalt adatoms are positioned to have maximal spatial overlap with the Hubbard band charge distribution. These resonance peaks disappear when the spatial overlap is reduced or when the magnetic impurities are replaced with non-magnetic impurities. Theoretical simulations using a modified Anderson impurity model integrated with a gapless quantum spin liquid show that these resonance peaks are consistent with a Kondo resonance induced by spinons combined with spinon-chargon binding effects that arise due to QSL gauge-field fluctuations.
Keywords
Cite
@article{arxiv.2202.07224,
title = {Evidence for a spinon Kondo effect in cobalt atoms on single-layer 1T-TaSe$_2$},
author = {Yi Chen and Wen-Yu He and Wei Ruan and Jinwoong Hwang and Shujie Tang and Ryan L. Lee and Meng Wu and Tiancong Zhu and Canxun Zhang and Hyejin Ryu and Feng Wang and Steven G. Louie and Zhi-Xun Shen and Sung-Kwan Mo and Patrick A. Lee and Michael F. Crommie},
journal= {arXiv preprint arXiv:2202.07224},
year = {2022}
}