Figure 3: Coulomb-enabled two-body scattering processes in graphene.

Shaded areas denote occupied states, in conduction and valence band, in a non-equilibrium state, at a given time. Arrows mark transitions from initial to final states. Coulomb collisions can take place between (a) electrons in the same band (intra-band scattering) or (b) between electrons in different bands (inter-band scattering). (c,d) Electrons can also scatter from one band to the other. These ‘Auger processes’ can either (c) increase (CM) or (d) decrease (Auger recombination) the conduction-band electrons.