Proximity-induced superconductivity in graphene

We propose a way of making graphene superconductive by putting on it small superconductive islands which cover a tiny fraction of graphene area. We show that the critical temperature, T_c, can reach several Kelvins at the experimentally accessible range of parameters. At low temperatures, TT_c, and zero magnetic field, the density of states is characterized by a small gap E_g ≤ T_c resulting from the collective proximity effect. Transverse magnetic field H_g(T) ∝ E_g is expected to destroy the spectral gap driving graphene layer to a kind of a superconductive glass state. Melting of the glass state into a metal occurs at a higher field H_g2(T).