Electric Breakdown of Percolation System of 2d Metal Film on Fullerene Underlayer

Abstract

Fullerene （Ｃ６０ and Ｃ7０）films were epitaxially grown on fresh (001) mica fcc closely-packed plane parallel to the substrate surface. Metal-overlayers were deposited onto these fullerene films in an ultra-hight-vacuum(UHV) chamber and in situ resistance measurements were performed. With increasing current, we observed reversible resistance variation and irreversible breakdown. Nera the percolation threshold we find power law scaling behavior Ｉb～Ｒ－α,where Ｉb is breakdown current and R the sample resistance. The exponent α is much smaller than the values given by previous experiments and prediction of conventional Ｎｏｄｅｓ-Ｌｉｎｋｓ-Ｂｌｏｂｓ(NLB) model. Possible explanation of these phenomena based on metal-fullerene interfacial interactions is discussed.