First principles study of the electronic energy bands and state density of lithium-doped narrow armchair graphene nanoribbons

• The electronic properties of Li-doped graphene nanoribbons are studied by first principles.
• The charge density is transferred between C and Li atoms and mainly located on the Li atom.
• The one-edge Li-doped AGNRs have the lowest formation energy.
• The Fermi level is located on the conduction band so that the Li-doped AGNRs become into metallic.
• A localization state is induced for the edge-doping AGNRs due to H-1s electronic states.

To understand the effect of lithium doping on graphene nanoribbons, Li-doped armchair graphene nanoribbons (AGNRs) are investigated using the local density approximation based on density function theory. The charge density, electronic energy band and density of states of bare, H terminated and Li-doped AGNRs are calculated. Our results indicate the charge density is transferred between C and Li atoms, and mainly located on the Li atom. The one-edge Li-doped AGNRs have the lowest formation energy. It can be predicted that one-edge Li-doped AGNRs is more close to the practice, while both-edge Li-doping is not so stable. The project density of states is calculated which reveals that the localization and hybridization between C-2p and Li-2s, 2p electronic states are much stronger in the conduction band. It causes the Fermi level is located on the conduction band so that the AGNRs become into metallic.