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