Electrically-tunable ultra-flat bands and $π$-electron magnetism in graphene nanoribbons

Fuente: arXiv
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Main Authors: Ma, Ruize, Tepliakov, Nikita V., Mostofi, Arash A., Pizzochero, Michele
Format: Preprint
Published: 2024
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author Ma, Ruize
Tepliakov, Nikita V.
Mostofi, Arash A.
Pizzochero, Michele
author_facet Ma, Ruize
Tepliakov, Nikita V.
Mostofi, Arash A.
Pizzochero, Michele
contents Atomically thin crystals hosting flat electronic bands have been recently identified as a rich playground for exploring and engineering strongly correlated phases. Yet, their variety remains limited, primarily to two-dimensional moiré superlattices. Here, we predict the formation of reversible, electrically-induced ultra-flat bands and $π$-electron magnetism in one-dimensional chevron graphene nanoribbons. Our $ab$ $initio$ calculations show that the application of a transverse electric field to these nanoribbons generates a pair of isolated, nearly perfectly flat bands with widths of approximately 1 meV around the Fermi level. Upon charge doping, these flat bands undergo a Stoner-like electronic instability, resulting in the spontaneous emergence of local magnetic moments at the edges of the otherwise non-magnetic nanoribbon, akin to a one-dimensional spin-$\frac{1}{2}$ chain. Our findings expand the class of carbon-based nanostructures exhibiting flat bands and establish a novel route for inducing correlated electronic phases in chevron graphene nanoribbons.
format Preprint
id arxiv_https___arxiv_org_abs_2412_15729
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Electrically-tunable ultra-flat bands and $π$-electron magnetism in graphene nanoribbons
Ma, Ruize
Tepliakov, Nikita V.
Mostofi, Arash A.
Pizzochero, Michele
Mesoscale and Nanoscale Physics
Materials Science
Atomically thin crystals hosting flat electronic bands have been recently identified as a rich playground for exploring and engineering strongly correlated phases. Yet, their variety remains limited, primarily to two-dimensional moiré superlattices. Here, we predict the formation of reversible, electrically-induced ultra-flat bands and $π$-electron magnetism in one-dimensional chevron graphene nanoribbons. Our $ab$ $initio$ calculations show that the application of a transverse electric field to these nanoribbons generates a pair of isolated, nearly perfectly flat bands with widths of approximately 1 meV around the Fermi level. Upon charge doping, these flat bands undergo a Stoner-like electronic instability, resulting in the spontaneous emergence of local magnetic moments at the edges of the otherwise non-magnetic nanoribbon, akin to a one-dimensional spin-$\frac{1}{2}$ chain. Our findings expand the class of carbon-based nanostructures exhibiting flat bands and establish a novel route for inducing correlated electronic phases in chevron graphene nanoribbons.
title Electrically-tunable ultra-flat bands and $π$-electron magnetism in graphene nanoribbons
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2412.15729