Intercalation of graphene on iridium with sodium atoms

It has been shown that sodium atoms deposited on the surface of graphene atop iridium at $T\le$ 850 K diffuse under the graphene layer into an intercalated state and accumulate there in significant concentrations $\sim$ (2–3) $\cdot$ 10$^{14}$ at/cm$^2$ . The release of the atoms from under the graphene “carpet” takes place upon destruction of the layer at $T\ge$ 1800 K. The physical nature of the differences in the processes of release of atoms of different alkali metals from under graphene has been discussed.