Electrical Contact Resistance in Graphite-Graphene contacts from ab initio methods

We study the ballistic transmission and the contact resistance ($R_c$) of a graphite-graphene contact in a top contact geometry from first principles. We find that the calculated $R_c$'s depend on the amount of graphene-graphite overlap, but quickly saturate for transfer lengths of the order of 20 {\AA}. For contacts overlapping more than this transfer length, the $R_c$ can be lower than the 100 {\Omega}$\cdot${\mu}m mark. On the other hand, edge graphite-graphene contacts are expected to have very low contact resistance.