Many-Body van der Waals Interactions between Graphitic Nanostructures

van der Waals interactions between finite-length single-wall carbon nanotubes and graphene nanoribbons are calculated including all many-body contributions. Comparative studies between the total two-, three-, four-, and many-body interaction energies are performed using the coupled dipole model. It is shown that the graphitic dispersive interaction is of truly collective nature. The combined effect of the size of the nanostructures, their anisotropy, orientations, and relative displacements can be captured accurately only when all many-body contributions are taken into account. This is of particular importance for nanotube and nanoribbon axial sliding, where the largest deviations between the few-body and many-body interaction energies are found.