Superatom orbitals ofSc3N@C80and their intermolecular hybridization onCu(110)−(2×1)-Osurface

Abstract

We investigate the electronic structure of an endohedral fullerene, ${\text{Sc}}_{3}{\text{N@C}}_{80}$, chemisorbed on $\text{Cu}(110)\text{\ensuremath{-}}(2\ifmmode\times\else\texttimes\fi{}1)\text{-O}$ surface by scanning tunneling microscopy and density-functional theory. Scanning tunneling microscopy and spectroscopy identify a series of delocalized atomlike superatom molecular orbitals (SAMOs) in the ${\text{Sc}}_{3}{\text{N@C}}_{80}$ and its aggregates. By contrast to ${\text{C}}_{60}$, the encapsulated ${\text{Sc}}_{3}\text{N}$ cluster in ${\text{Sc}}_{3}{\text{N@C}}_{80}$ distorts the nearly-spherical central potential of the carbon cage, imparting an asymmetric spatial distribution to the SAMOs. When ${\text{Sc}}_{3}{\text{N@C}}_{80}$ molecules form dimers and trimers, however, the strong intermolecular hybridization results in highly symmetric hybridized SAMOs with clear bonding and antibonding characteristics. The electronic-structure calculations on ${\text{Sc}}_{3}{\text{N@C}}_{80}$ and its aggregates confirm the existence of SAMOs and reproduce their hybridization as observed in the experiment.