Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?

Abstract Magic-angle twisted bilayer graphene (MATBG) exhibits a panoply of many-body phenomena that are intimately tied to the appearance of narrow and well-isolated electronic bands. The microscopic ingredients that are responsible for the complex experimental phenomenology include electron–electr...

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Autores principales:	Cyprian Lewandowski, Stevan Nadj-Perge, Debanjan Chowdhury
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
Acceso en línea:	https://doaj.org/article/c3420fce04f54ac0b93cf636c5202371
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spelling	oai:doaj.org-article:c3420fce04f54ac0b93cf636c52023712021-12-02T17:37:42ZDoes filling-dependent band renormalization aid pairing in twisted bilayer graphene?10.1038/s41535-021-00379-62397-4648https://doaj.org/article/c3420fce04f54ac0b93cf636c52023712021-09-01T00:00:00Zhttps://doi.org/10.1038/s41535-021-00379-6https://doaj.org/toc/2397-4648Abstract Magic-angle twisted bilayer graphene (MATBG) exhibits a panoply of many-body phenomena that are intimately tied to the appearance of narrow and well-isolated electronic bands. The microscopic ingredients that are responsible for the complex experimental phenomenology include electron–electron (phonon) interactions and nontrivial Bloch wavefunctions associated with the narrow bands. Inspired by recent experiments, we focus on two independent quantities that are considerably modified by Coulomb interaction-driven band renormalization, namely the density of states and the minimal spatial extent associated with the Wannier functions. First, we show that a filling-dependent enhancement of the density of states, caused by band flattening, in combination with phonon-mediated attraction due to electron-phonon umklapp processes, increases the tendency towards superconducting pairing in a range of angles around magic-angle. Second, we demonstrate that the minimal spatial extent associated with the Wannier functions, which contributes towards increasing the superconducting phase stiffness, also develops a nontrivial enhancement due to the interaction-induced renormalization of the Bloch wavefunctions. While our modeling of superconductivity (SC) assumes a weak electron-phonon coupling and does not consider many of the likely relevant correlation effects, it explains simply the experimentally observed robustness of SC in the wide range of angles that occurs in the relevant range of fillings.Cyprian LewandowskiStevan Nadj-PergeDebanjan ChowdhuryNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492Atomic physics. Constitution and properties of matterQC170-197ENnpj Quantum Materials, Vol 6, Iss 1, Pp 1-9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197 Cyprian Lewandowski Stevan Nadj-Perge Debanjan Chowdhury Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
description	Abstract Magic-angle twisted bilayer graphene (MATBG) exhibits a panoply of many-body phenomena that are intimately tied to the appearance of narrow and well-isolated electronic bands. The microscopic ingredients that are responsible for the complex experimental phenomenology include electron–electron (phonon) interactions and nontrivial Bloch wavefunctions associated with the narrow bands. Inspired by recent experiments, we focus on two independent quantities that are considerably modified by Coulomb interaction-driven band renormalization, namely the density of states and the minimal spatial extent associated with the Wannier functions. First, we show that a filling-dependent enhancement of the density of states, caused by band flattening, in combination with phonon-mediated attraction due to electron-phonon umklapp processes, increases the tendency towards superconducting pairing in a range of angles around magic-angle. Second, we demonstrate that the minimal spatial extent associated with the Wannier functions, which contributes towards increasing the superconducting phase stiffness, also develops a nontrivial enhancement due to the interaction-induced renormalization of the Bloch wavefunctions. While our modeling of superconductivity (SC) assumes a weak electron-phonon coupling and does not consider many of the likely relevant correlation effects, it explains simply the experimentally observed robustness of SC in the wide range of angles that occurs in the relevant range of fillings.
format	article
author	Cyprian Lewandowski Stevan Nadj-Perge Debanjan Chowdhury
author_facet	Cyprian Lewandowski Stevan Nadj-Perge Debanjan Chowdhury
author_sort	Cyprian Lewandowski
title	Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
title_short	Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
title_full	Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
title_fullStr	Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
title_full_unstemmed	Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
title_sort	does filling-dependent band renormalization aid pairing in twisted bilayer graphene?
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/c3420fce04f54ac0b93cf636c5202371
work_keys_str_mv	AT cyprianlewandowski doesfillingdependentbandrenormalizationaidpairingintwistedbilayergraphene AT stevannadjperge doesfillingdependentbandrenormalizationaidpairingintwistedbilayergraphene AT debanjanchowdhury doesfillingdependentbandrenormalizationaidpairingintwistedbilayergraphene
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Does filling-dependent band renormalization aid pairing in twisted bilayer graphene?

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