Novel Interface Properties of Au Overlayer on Top of C₆₀ Polycrystalline Film

Abstract

From a temperature dependence of the dark electrical conductivity of Au overlayer σM(T) measured along the interface direction on top of a C60 polycrystalline film, a dramatic change in σM is observed at T ≈255 K; σM(T) increases with increasing temperature. As deduced from σM versus 1/T, an activation energy of 200 ±30 meV for T<255 K is much larger than that of 59 ±2 meV for T>255 K. These novel phenomena are explained by structural–electronic interaction on the Au/C60 interface with a change in the properties of the induced surface states due to the rotational order/disorder phase transition.