Graphene Nanoribbon Superconductor

The possibility of the s-wave superconductive state in armchair graphene nanoribbons is studied within the attractive Hubbard model, standard BCS theory, and Green’s function approach. Bogoliubov de Gennes equations are derived for this system in the singlet state. A nonzero critical temperature is found which depends on the width of the system. This critical temperature decreases as the width of the system increases and for sufficiently large widths, its value reaches a constant amount which could be taken as the critical temperature of the graphene sheet. The critical temperature also depends on band-filling which, around half band-filling, shows a maximum. However, at half-filling, it drops to a lower value less than its maximum.