Flat-Band Driven Kondo Breakdown and Reentrant Effects in Heavy-Fermion Moiré Superlattices

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Main Authors: Eickhoff, Fabian, Zhu, Jian-Xin, Fauseweh, Benedikt
Format: Preprint
Published: 2025
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author Eickhoff, Fabian
Zhu, Jian-Xin
Fauseweh, Benedikt
author_facet Eickhoff, Fabian
Zhu, Jian-Xin
Fauseweh, Benedikt
contents Moiré superlattices (MSLs) in van der Waals (vdW) heterostructures have demonstrated their incredible power in driving emergent electronic phenomena, some of which are reminiscent of those usually only observed in bulk strongly correlated quantum materials. With the recent discovery of van der Waals $f$-electron materials, the design of novel MSLs of intrinsic strong correlation is now within the reach. Here we study the novel electron phases of two-dimensional heavy-fermion MSL with increasingly diluted f-electron local moments. By applying dynamical mean field theory (DMFT) with numerical renormalization group (NRG) as an impurity solver, we demonstrate the appearance of a new energy scale and a re-entrant Kondo breakdown in connection with the emergence of a flat band in the system. We further compare our numerical findings with predictions derived from the Lieb-Mattis theorem and show the necessity of the new energy scale to consistently reconcile the predictions with the conventional single-impurity limit for exceedingly large unit cells.
format Preprint
id arxiv_https___arxiv_org_abs_2502_06360
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Flat-Band Driven Kondo Breakdown and Reentrant Effects in Heavy-Fermion Moiré Superlattices
Eickhoff, Fabian
Zhu, Jian-Xin
Fauseweh, Benedikt
Strongly Correlated Electrons
Moiré superlattices (MSLs) in van der Waals (vdW) heterostructures have demonstrated their incredible power in driving emergent electronic phenomena, some of which are reminiscent of those usually only observed in bulk strongly correlated quantum materials. With the recent discovery of van der Waals $f$-electron materials, the design of novel MSLs of intrinsic strong correlation is now within the reach. Here we study the novel electron phases of two-dimensional heavy-fermion MSL with increasingly diluted f-electron local moments. By applying dynamical mean field theory (DMFT) with numerical renormalization group (NRG) as an impurity solver, we demonstrate the appearance of a new energy scale and a re-entrant Kondo breakdown in connection with the emergence of a flat band in the system. We further compare our numerical findings with predictions derived from the Lieb-Mattis theorem and show the necessity of the new energy scale to consistently reconcile the predictions with the conventional single-impurity limit for exceedingly large unit cells.
title Flat-Band Driven Kondo Breakdown and Reentrant Effects in Heavy-Fermion Moiré Superlattices
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2502.06360