Kondo effect and spin-orbit coupling in graphene quantum dots
Abstract
The Kondo effect is a cornerstone in the study of strongly correlated fermions. The coherent exchange coupling of conduction electrons to local magnetic moments gives rise to a Kondo cloud that screens the impurity spin. Whereas complete Kondo screening has been explored widely, realizations of the underscreened scenario - where only some of several Kondo channels participate in the screening - remain rare. Here we report the observation of fully screened and underscreened Kondo effects in quantum dots in bilayer graphene. More generally, we introduce a unique platform for studying Kondo physics. In contrast to carbon nanotubes, whose curved surfaces give rise to strong spin-orbit coupling breaking the SU(4) symmetry of the electronic states relevant for the Kondo effect, we study a nominally flat carbon material with small spin-orbit coupling. Moreover, the unusual two-electron triplet ground state in bilayer graphene dots provides a route to exploring the underscreened spin-1 Kondo effect.
Keywords
Cite
@article{arxiv.2103.04864,
title = {Kondo effect and spin-orbit coupling in graphene quantum dots},
author = {Annika Kurzmann and Yaakov Kleeorin and Chuyao Tong and Rebekka Garreis and Angelika Knothe and Marius Eich and Christopher Mittag and Carolin Gold and Folkert K. de Vries and Kenji Watanabe and Takashi Taniguchi and Vladimir Fal'ko and Yigal Meir and Thomas Ihn and Klaus Ensslin},
journal= {arXiv preprint arXiv:2103.04864},
year = {2022}
}