Tuning a two-impurity Kondo system by a moiré superstructure

Abstract

Two-impurity Kondo models are paradigmatic for correlated spin-fermion systems. Working with Mn atoms on Au(111) covered by a monolayer of MoS${}_2$, we tune the inter-adatom exchange via the adatom distance and the adatom-substrate exchange via the location relative to a moiré structure of the substrate. Differential-conductance measurements on isolated adatoms exhibit Kondo peaks with heights depending on the adatom location relative to the moiré structure. Mn dimers spaced by a few atomic lattice sites exhibit split Kondo resonances. In contrast, adatoms in closely spaced dimers couple antiferromagnetically, resulting in a molecular-singlet ground state. Exciting the singlet-triplet transition by tunneling electrons, we find that the singlet-triplet splitting is surprisingly sensitive to the moiré structure. We interpret our results theoretically by relating the variations in the singlet-triplet splitting to the heights of the Kondo peaks of single adatoms, finding evidence for coupling of the adatom spin to multiple conduction electron channels.

References in corpus (4)

• Exchange interaction between single magnetic adatoms
• Orbital Picture of Yu-Shiba-Rusinov Multiplets
• Interplay between Kondo effect and Ruderman-Kittel-Kasuya-Yosida interaction
• Moiré tuning of spin excitations: Individual Fe atoms on MoS${}_2$/Au(111)

Cited by in corpus (8)

• Electronic and magnetic properties of single chalcogen vacancies in MoS${}_2$/Au(111)
• Topological quantum phase transition in individual Fe Atoms on MoS${}_2$/Au(111)
• Probing the spin polarization of an Anderson impurity
• Universal Crossover in the Three-Channel Charge Kondo Model at High Transparency
• Unraveling screening mechanisms in Kondo impurities using an NRG-MPS-based method
• Vibration-assisted tunneling through single Au adatoms on two-dimensional WSe2
• Direct signatures of $d$-level hybridization and dimerization in magnetic adatom chains on a superconductor
• Epitaxial two-dimensional membranes under intrinsic and extrinsic strains