Graphene energy loss spectroscopy: Perpendicular case

The energy loss of a fast charged particle probe incident on a two-dimensional graphene sheet is examined here. The fast particle motion is taken to be perpendicular to the 2D graphene sheet, which is considered to be in the degenerate limit of zero temperature. The response dynamics of the 2D graphene layer are described in the random phase approximation and the energy loss for particle motion perpendicular to the 2D graphene layer is calculated as a function of the velocity of the charged particle.