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 Mn12 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 Mn12 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 Mn12 clusters. The authors discuss these findings in the light of the recent band structure calculations and electronic transport measurements on single Mn12 molecules.