Experimental observation of a band gap in individual Mn12 molecules on Au(111)

The authors report on the electronic properties of individual molecules of two Mn-12 derivatives chemically grafted on the functionalized Au(111) surface studied by means of ultrahigh vacuum scanning tunneling microscopy/spectroscopy at room temperature. Reproducible current-voltage curves were obtained from both Mn-12 molecules, showing a well defined wide band gap. In agreement with the tunneling spectroscopy results, the bias voltage variation upon scanning leads to apparent height changes of the Mn-12 clusters. The authors discuss these findings in the light of the recent band structure calculations and electronic transport measurements on single Mn-12 molecules. (c) 2007 American Institute of Physics.