Strong correlation effect in Fullerene C20*

Successful synthesis of the gas-phase dodecahedral C20 molecule [Nature 407, 60 (2000)] has stimulated great interest in this material. In this talk we report exact diagonalization and quantum Monte Carlo simulation results on the C20 molecule and a possible solid structure [Phys. Rev. B 76, 033414 (2007)]. Our results suggest that strong electronic correlations suppress the Jahn-Teller effect on the dodecahedral molecule, and make the solid an insulator. We also determine the critical value of the interaction strength for the metal-insulator transition.