2003/05/31 by Samuel Wehrli, S. Wehrli, Erik Koch +3
Chemistry · Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #Fullerene Chemistry and Applications #Graphene research and applications #cond-mat
paper · pdf · doi:10.1103/physrevb.68.115412
published as Phys. Rev. B 68, 115412 (2003) · 14 pages, 13 figures, submitted to PRB
arxiv created 2003/07/21 · openalex publication_date 2003/09/12 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate the possibility of doping C60 crystals by applying a strong electric field. For an accurate description of a C60 field-effect device we introduce a multipole expansion of the field, the response of the C60 molecules, and the Stark splitting of the molecular levels. The relevant response coefficients and splittings are calculated ab initio for several high symmetry orientations. Using a group theoretic analysis we extend these results to arbitrary orientations of the C60 molecules with respect to the external field. We find that, surprisingly, for the highest occupied and the lowest unoccupied molecular orbital, respectively, the two leading multipole components lift the degeneracy of the molecular level in the same way. Moreover the relative signs of the splittings turn out to be such that the splittings add up when the external field induces charge into the respective level. That means that when charge carriers are put into a level, its electronic structure is strongly modified. Therefore, in general, in C60 field-effect devices charge is not simply put into otherwise unchanged bands, so already because of this their physics should be quite different from that of the alkali-doped fullerenes.