Magnetic Triplet Excitations in Graphene – Niels Bohr Institute - University of Copenhagen

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Magnetic Triplet Excitations in Graphene

When doping graphene an unique window appears in the electron–hole excitation spectrum. Including the Coulomb interaction through the Hubbard Hamiltonian results in bound state formation in graphene. The bound states we analyze represent triplet excitations, i.e. magnons, with spin 1. When increasing the strength of the Coulomb interaction, electron–hole pairs are dragged down into the window. This is a property of the triplet excitations since the interaction term is negative, indicating attraction, in that context. We analyzed further the dispersion relation for U ≈ 11 eV and at last we investigated the appearance of magnons in real space.

Master Thesis by Logi Arnarson