Revealing the Conformational Dynamics in a Single-Molecule Junction by Site- and Angle-Resolved Dynamic Probe Method

Single-molecule junctions have been extensively studied because of their high potential for future nanoscale device applications as well as their importance in basic studies for molecular science and technology. However, since the bonding sites at an electrode and the molecular tilt angles, for example, cannot be determined experimentally, analyses have been performed assuming the structures of such interactive key factors, with uncertainties and inconsistencies remaining in the proposed mechanisms. We have developed a methodology that enables the probing of conformational dynamics in single-molecule junctions simultaneously with the direct characterization of molecular bonding sites and tilt angles. This technique has revealed the elemental processes in single-molecule junctions, which have not been clarified using conventional methods. The mechanisms of the molecular dynamics in 1,4-benzenedithiol and 4,4′-bipyridine single-molecule junctions, which, for example, produce binary conductance switching of different types, were clearly discriminated and comprehensively explained

STM and STS Studies on the Density of States Modulation of Pr@C₈₂ and Sc₃C₂@C₈₀ Binary-Metallofullerene Peapods

The density of states modulation of single-wall carbon nanotubes (SWCNTs) is induced by the encapsulation of two different kinds of metallofullerenes (Pr@C₈₂ and Sc₃C₂@C₈₀). We report the observation of the modulated density of states using scanning tunneling microscopy/spectroscopy, where the modulation is successfully reproduced by density functional theory calculation. The metallofullerene molecules in SWCNTs strongly affect the local band structures of SWCNTs. The present findings show that the local electronic structures of SWCNTs can be modified by not only varying the geometric structures of SWCNTs but also the varieties of metallofullerenes encapsulated