Superatom molecular orbitals: a new type of long-lived electronic states

TL;DR

This paper uses ab initio calculations to analyze superatom molecular orbitals (SAMOs) in fullerenes, revealing their long-lived nature and potential for molecular electronics, and explaining their stability through Fock-space localization.

Contribution

It provides the first ab initio explanation for the stability and longevity of SAMOs, connecting them to Fock-space localization and expanding understanding of electronic states in fullerenes.

Findings

SAMOs are long-lived, delocalized electronic states in fullerenes.

The calculations explain the stability of SAMOs observed experimentally.

SAMOs are good candidates for molecular electronic applications.

Abstract

We present ab initio calculations of the quasiparticle decay times in a Buckminsterfullerene based on the many-body perturbation theory. A particularly lucid representation arises when the broadening of the quasiparticle states is plotted in the angular momentum and energy coordinates. In this representation the main spectroscopic features of the fullerene consist of two occupied nearly parabolic bands, and delocalized plane-wave-like unoccupied states with a few long-lived electronic states (the superatom molecular orbitals, SAMOs) embedded in the continuum of Fermi-liquid states. SAMOs have been recently uncovered experimentally by M. Feng, J. Zhao, and H. Petek [Science 320, 359 (2008)] using scanning tunneling spectroscopy. The present calculations offer an explanation of their unusual stability and unveil their long-lived nature making them good candidates for applications in the molecular electronics. From the fundamental point of view these states illustrate a concept of the Fock-space localization [B. L. Altshuler, Y. Gefen, A. Kamenev, and L. S. Levitov, Phys. Rev. Lett. 78, 2803 (1997)] with properties drastically different from the Fermi-liquid excitations.