Abstract
The isolated neutral molecule is characterized by a triply degenerate lowest unoccupied level of symmetry. In the alkali-metal-intercalated 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 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 to behave as a negative-U system. We finally relate the dimensionless electron-phonon coupling constant λ to the magnitude of the Jahn-Teller energies.
- Received 3 September 1991
DOI:https://doi.org/10.1103/PhysRevB.44.12106
©1991 American Physical Society