000161978 001__ 161978 000161978 005__ 20251017144603.0 000161978 0247_ $$2doi$$a10.1038/s41467-025-60767-5 000161978 0248_ $$2sideral$$a144618 000161978 037__ $$aART-2025-144618 000161978 041__ $$aeng 000161978 100__ $$0(orcid)0000-0001-8253-8741$$aDomínguez-Celorrio, Amelia 000161978 245__ $$aSystematic modulation of charge and spin in graphene nanoribbons on MgO 000161978 260__ $$c2025 000161978 5060_ $$aAccess copy available to the general public$$fUnrestricted 000161978 5203_ $$aIn order to take full advantage of graphene nanostructures in quantum technologies, their charge and spin state must be precisely controlled. Graphene quantum dots require external gating potentials to tune their ground state. Here, we show systematic manipulation of the electron occupation in graphene nanoribbons lying on MgO layers grown on Ag(001). Owing to the efficient electronic decoupling character of MgO, and the electropositive nature of the substrate, the ribbons host an integer number of electrons that depend on their length and shape. This results in the alternation between a non-magnetic closed-shell state and an open-shell paramagnetic system for even and odd electron occupations respectively. For the odd case, we find a narrow Coulomb correlation gap, which is the smoking gun of its spin-½ state. Comparisons of scanning tunnelling microscopy data with mean-field Hubbard simulations confirm the discretization of the ribbons’ electronic states and charge excess of up to 19 electrons per ribbon. 000161978 536__ $$9info:eu-repo/grantAgreement/ES/DGA/E13-23R$$9info:eu-repo/grantAgreement/EUR/ERDF/EFA194-16TNSI$$9info:eu-repo/grantAgreement/ES/MCIU/PID2019-107338RB-C64$$9info:eu-repo/grantAgreement/ES/MICINN AEI/PID2022-138750NB-C21$$9info:eu-repo/grantAgreement/ES/MICIU/CEX2023-001286-S 000161978 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es 000161978 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000161978 700__ $$aEdens, Leonard 000161978 700__ $$aSanz, Sofía 000161978 700__ $$aVilas-Varela, Manuel 000161978 700__ $$aMartinez-Castro, Jose 000161978 700__ $$aPeña, Diego 000161978 700__ $$aLanglais, Véronique 000161978 700__ $$aFrederiksen, Thomas 000161978 700__ $$aPascual, José I. 000161978 700__ $$0(orcid)0000-0002-3260-9641$$aSerrate, David 000161978 773__ $$g16 (2025), 5632 [8 pp.]$$tNature communications$$x2041-1723 000161978 8564_ $$s2440356$$uhttps://zaguan.unizar.es/record/161978/files/texto_completo.pdf$$yVersión publicada 000161978 8564_ $$s2714563$$uhttps://zaguan.unizar.es/record/161978/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000161978 909CO $$ooai:zaguan.unizar.es:161978$$particulos$$pdriver 000161978 951__ $$a2025-10-17-14:14:37 000161978 980__ $$aARTICLE