Abstract
Antiferromagnetism of stacked nanographite is investigated using the Hubbard-type model. We find that the open shell electronic structure can be an origin of the decreasing magnetic moment with decreasing inter-layer distance, as experiments of adsorption of molecules suggest. Next, possible charge-separated states are considered using the extended Hubbard model with nearest-neighbor repulsive interactions. The charge-polarized state could appear, when a static electric field is present in the graphene plane for example. Finally, superperiodic patterns with a long distance in a nanographene sheet observed by STM are discussed in terms of the interference of electronic wave functions with a static linear potential theoretically. In the analysis by the k • p model, the oscillation period decreases spatially in agreement with experiments.
