Isotopic disorder and the electronic pairing mechanism in superconducting fullerenes.

Abstract

We examine the effects of isotopic disorder on the shift of ${\mathit{T}}_{\mathit{c}}$ in the superconducting fullerenes within the electronic pairing mechanism of Chakravarty et al. Isotopic disorder leads to anisotropic changes in electronic hopping on an individual fullerene molecule, which in turn slightly alters the pair binding energy on that molecule. While isotopic disorder does tend to suppress ${\mathit{T}}_{\mathit{c}}$ within this model, we find that these effects are too small to account for anomalous isotope shifts reported for partial $^{13}\mathrm{C}$ substitution.