Exchange Splitting in Graphene Quantum Dots Induced by Single-Molecule Magnet Mn₁₂

When the single-molecule magnet, Mn₁₂-CHCl₂ is deposited on graphene quantum dot devices, transport measurements show that the current through the devices switches between two or more discrete states. This current switching is attributed to magnetic state switching in the molecules, which results in spin-splitting in the graphene. Using a thermal activation model, the size of the splitting has been estimated to be up to hundreds of µeV. Density functional theory analysis shows agreement with estimates from experimental data. When a molecule of Mn₁₂-CHCl­₂ is added to a graphene lattice, energy levels near the Dirac cone in graphene are split by up to 500 µeV.