Koller, S.S.KollerMayrhofer, L.L.MayrhoferGrifoni, M.M.Grifoni2022-03-042022-03-042009https://publica.fraunhofer.de/handle/publica/21994210.1209/0295-5075/88/57001We present a microscopic theory for interacting graphene armchair nanoribbon quantum dots. Long range interaction processes are responsible for Coulomb blockade and spin-charge separation. Short range ones, arising from the underlying honeycomb lattice of graphene, smear the spin-charge separation and induce exchange correlations between bulk electrons - delocalized on the ribbon - and single electrons localized at the two ends. As a consequence, entangled end-bulk states where the bulk spin is no longer a conserved quantity occur. Entanglement's signature is the occurrence of negative differential conductance effects in a fully symmetric set-up due to symmetry-forbidden transitions.enPACS 73.23.HkPACS 73.63.-bPACS 71.10.Pmcoulomb blockadesingle-electron tunnelingfermions in reduced dimensionselectronic transport in nanoscale materials and structures620530journal article