Systematic modulation of charge and spin in graphene nanoribbons on MgO

Abstract In order to take full advantage of graphene nanostructures in quantum technologies, their charge and spin state must be precisely controlled. Graphene quantum dots require external gating potentials to tune their ground state. Here, we show systematic manipulation of the electron occupation...

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Main Authors: Amelia Domínguez-Celorrio, Leonard Edens, Sofía Sanz, Manuel Vilas-Varela, Jose Martinez-Castro, Diego Peña, Véronique Langlais, Thomas Frederiksen, José I. Pascual, David Serrate
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-60767-5
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author Amelia Domínguez-Celorrio
Leonard Edens
Sofía Sanz
Manuel Vilas-Varela
Jose Martinez-Castro
Diego Peña
Véronique Langlais
Thomas Frederiksen
José I. Pascual
David Serrate
author_facet Amelia Domínguez-Celorrio
Leonard Edens
Sofía Sanz
Manuel Vilas-Varela
Jose Martinez-Castro
Diego Peña
Véronique Langlais
Thomas Frederiksen
José I. Pascual
David Serrate
author_sort Amelia Domínguez-Celorrio
collection DOAJ
description Abstract In order to take full advantage of graphene nanostructures in quantum technologies, their charge and spin state must be precisely controlled. Graphene quantum dots require external gating potentials to tune their ground state. Here, we show systematic manipulation of the electron occupation in graphene nanoribbons lying on MgO layers grown on Ag(001). Owing to the efficient electronic decoupling character of MgO, and the electropositive nature of the substrate, the ribbons host an integer number of electrons that depend on their length and shape. This results in the alternation between a non-magnetic closed-shell state and an open-shell paramagnetic system for even and odd electron occupations respectively. For the odd case, we find a narrow Coulomb correlation gap, which is the smoking gun of its spin-½ state. Comparisons of scanning tunnelling microscopy data with mean-field Hubbard simulations confirm the discretization of the ribbons’ electronic states and charge excess of up to 19 electrons per ribbon.
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series Nature Communications
spelling doaj-art-266e8446500b4a7ea3e8adf45a71eb9a2025-08-20T03:45:35ZengNature PortfolioNature Communications2041-17232025-07-011611810.1038/s41467-025-60767-5Systematic modulation of charge and spin in graphene nanoribbons on MgOAmelia Domínguez-Celorrio0Leonard Edens1Sofía Sanz2Manuel Vilas-Varela3Jose Martinez-Castro4Diego Peña5Véronique Langlais6Thomas Frederiksen7José I. Pascual8David Serrate9Insituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de ZaragozaCIC NanoGUNE BRTADonostia International Physics CenterCentro Singular de Investigación en Química Bilóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de CompostelaPeter Grünberg Institut (PGI-3), Forschungszentrum JülichCentro Singular de Investigación en Química Bilóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de CompostelaCentre d’Elaboration de Materiaux et d’Etudes Structurales, CNRSDonostia International Physics CenterCIC NanoGUNE BRTAInsituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de ZaragozaAbstract In order to take full advantage of graphene nanostructures in quantum technologies, their charge and spin state must be precisely controlled. Graphene quantum dots require external gating potentials to tune their ground state. Here, we show systematic manipulation of the electron occupation in graphene nanoribbons lying on MgO layers grown on Ag(001). Owing to the efficient electronic decoupling character of MgO, and the electropositive nature of the substrate, the ribbons host an integer number of electrons that depend on their length and shape. This results in the alternation between a non-magnetic closed-shell state and an open-shell paramagnetic system for even and odd electron occupations respectively. For the odd case, we find a narrow Coulomb correlation gap, which is the smoking gun of its spin-½ state. Comparisons of scanning tunnelling microscopy data with mean-field Hubbard simulations confirm the discretization of the ribbons’ electronic states and charge excess of up to 19 electrons per ribbon.https://doi.org/10.1038/s41467-025-60767-5
spellingShingle Amelia Domínguez-Celorrio
Leonard Edens
Sofía Sanz
Manuel Vilas-Varela
Jose Martinez-Castro
Diego Peña
Véronique Langlais
Thomas Frederiksen
José I. Pascual
David Serrate
Systematic modulation of charge and spin in graphene nanoribbons on MgO
Nature Communications
title Systematic modulation of charge and spin in graphene nanoribbons on MgO
title_full Systematic modulation of charge and spin in graphene nanoribbons on MgO
title_fullStr Systematic modulation of charge and spin in graphene nanoribbons on MgO
title_full_unstemmed Systematic modulation of charge and spin in graphene nanoribbons on MgO
title_short Systematic modulation of charge and spin in graphene nanoribbons on MgO
title_sort systematic modulation of charge and spin in graphene nanoribbons on mgo
url https://doi.org/10.1038/s41467-025-60767-5
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