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Title: Jahn-Teller effect for the negatively charged C sub 60 molecule: Analogy with the silicon vacancy

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ;  [1];  [2]
  1. AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)
  2. Department of Physics and Astronomy and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824-1116 (United States)

The isolated neutral C{sub 60} molecule is characterized by a triply degenerate lowest unoccupied level of {ital t}{sub 1{ital u}} symmetry. In the alkali-metal-intercalated C{sub 60} crystals, this state is partially filled and is thus subject to a Jahn-Teller distortion. To examine the relation between this effect and the superconducitvity of these crystals, we first study the stable atomic distortions as a function of the occupancy of the {ital t}{sub 1{ital u}} state, stressing the similarity between this problem and the single vacancy in silicon. We then show that the on-ball electron-lattice coupling is not strong enough for C{sub 60} to behave as a negative-{ital U} system. We finally relate the dimensionless electron-phonon coupling constant {lambda} to the magnitude of the Jahn-Teller energies.

OSTI ID:
5079336
Journal Information:
Physical Review, B: Condensed Matter; (United States), Vol. 44:21; ISSN 0163-1829
Country of Publication:
United States
Language:
English