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Main Authors: Fischer, Max, Poli, Arianna, Crippa, Lorenzo, Călugăru, Dumitru, Ciuchi, Sergio, Vojta, Matthias, Toschi, Alessandro, Sangiovanni, Giorgio
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2503.14326
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author Fischer, Max
Poli, Arianna
Crippa, Lorenzo
Călugăru, Dumitru
Ciuchi, Sergio
Vojta, Matthias
Toschi, Alessandro
Sangiovanni, Giorgio
author_facet Fischer, Max
Poli, Arianna
Crippa, Lorenzo
Călugăru, Dumitru
Ciuchi, Sergio
Vojta, Matthias
Toschi, Alessandro
Sangiovanni, Giorgio
contents The Kondo screening of a localized magnetic moment crucially depends on the spectral properties of the electronic bath to which it is coupled. Unlike textbook examples, realistic systems as well as dynamical mean-field theory of correlated lattice models force us to explicitly consider sharp features in the hybridization function near the Fermi energy. A case currently under the spotlight is twisted bilayer graphene, where the hybridization function of the heavy-fermion-like bands to the itinerant ones displays a divergence. We clarify how this impacts the screening mechanisms by means of a toy model with a tunable $δ$-peak in the hybridization function, superimposed to a regular part. Our analysis unveils an unexpectedly big impact on the Kondo screening already for a parametrically small weight of the flat band in the bath.
format Preprint
id arxiv_https___arxiv_org_abs_2503_14326
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fragility of local moments against hybridization with flat bands
Fischer, Max
Poli, Arianna
Crippa, Lorenzo
Călugăru, Dumitru
Ciuchi, Sergio
Vojta, Matthias
Toschi, Alessandro
Sangiovanni, Giorgio
Strongly Correlated Electrons
The Kondo screening of a localized magnetic moment crucially depends on the spectral properties of the electronic bath to which it is coupled. Unlike textbook examples, realistic systems as well as dynamical mean-field theory of correlated lattice models force us to explicitly consider sharp features in the hybridization function near the Fermi energy. A case currently under the spotlight is twisted bilayer graphene, where the hybridization function of the heavy-fermion-like bands to the itinerant ones displays a divergence. We clarify how this impacts the screening mechanisms by means of a toy model with a tunable $δ$-peak in the hybridization function, superimposed to a regular part. Our analysis unveils an unexpectedly big impact on the Kondo screening already for a parametrically small weight of the flat band in the bath.
title Fragility of local moments against hybridization with flat bands
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.14326