Andersen Group El.-Phon. QMC C60 GW Resistivity saturation

Jahn-Teller effects

The Jahn-Teller effect has been studied for the photoemission from negatively charged C60 molecules (Phys. Rev. Lett. 47, 1875 (1995)). It was found that the Jahn-Teller effect strongly influences the estimates of the electron-phonon interaction.
The influence of the Jahn-Teller effect on the effective Coulomb interaction has been studied ( Phys. Rev. B 51, 3493 (1995)). It was found that for this property the system behaves essentially as being in the strong coupling limit.
The g-factor has been investigated ( Phys. Rev. B 54, 17184 (1995)). The orbital moment has a large contribution from the l=5 character of the orbital, but is reduced by the Jahn-Teller effect due to a Ham factor. The effective spin-orbit coupling, which couples the orbital and spin moments, is drastically reduced by the small C60 curvature. An effective g-factor substantially smaller than 2 is expected for the free molecule.
The (dynamical) Jahn-Teller effect is found to play an essential role for the metal-insulator transition in AnC60. In particular, the Jahn-Teller effect is responsible for the A4C60 being nonmmagnetic.

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Andersen Group Max-Planck-Institut für Festkörperforschung
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