Dynamical Jahn--Teller effect and antiferromagnetism in Cs${}_3$C${}_{60}$

Abstract

The dynamical Jahn--Teller effect on fullerene sites in insulating Cs${}_3$C${}_{60}$ is investigated fully ab initio. The vibronic excitations of rotational type are at $\ge$65 cm${}^{-1}$ while the net kinetic contribution to the Jahn--Teller stabilization energy constitutes ca 90 meV. This means that no localization of distortions by intermolecular interactions is possible in these fullerides, therefore, free rotations of deformations take place independently on each C${}_{60}$. The latter destroy the orbital ordering and establish a conventional exchange interaction between $S=1/2$ on fullerene sites. The corresponding exchange model is derived and predicts the Néel temperature for A15 Cs${}_3$C${}_{60}$ close to experiment.

8 pages, 2 figures

References in corpus (4)

• Modeling the Unconventional Superconducting Properties of Expanded A${}_3$C${}_{60}$ Fullerides
• NMR study of the Mott transitions to superconductivity in the two Cs_3C_60 phases
• Vibronic coupling in C${}_{60}^{-}$ anion revisited: Precise derivations from photoelectron spectra and DFT calculations
• The Mott State and Superconductivity in Face-Centred Cubic Structured Cs3C60: A 133Cs-Nuclear Magnetic Resonance Study under Pressure

Cited by in corpus (3)

• Dynamical Jahn--Teller instability in metallic fullerides
• Jahn-Teller effect in cubic fullerides A${}_3$C${}_{60}$
• Nanoscale orbital excitations and the infrared spectrum of a molecular Mott insulator: A15-Cs${}_3$C${}_{60}$