Analysis of low-voltage i(V) characteristics of a single c60 molecule

We demonstrate experimentally with an STM operating in ultra-high vacuum and with model calculations that the current-voltage characteristics of a single Cgo molecule are linear at low voltage. This is shown to prevail for tip-surface separations larger than the electrical contact point down to when the molecule is physically compressed by the tip. This linear I(V) relationship of a single molecule holds in general as long as its HOMO-LUMO gap in the junction exceeds the voltage used to define the junction electrical resistance and if the molecule is enough coupled to the electrodes. © 1995 IOP Publishing Ltd.