Tight-Binding Parametrization of First-Principles Electronic Dispersion in Orientationally Disordered A3c60
Abstract
We derive numerical tight-binding hopping parameters to describe conduction-band dispersion in arbitrary orientational phases of
A
3
C
60
. The parameters are obtained by direct Fourier inversion of the spectra from self-consistent electronic-structure calculations for K
3
C
60
using the local-density approximation, including the effects of orientational dependence. Using the new parameters, we revisit several earlier investigations of the orientational ordering in
A
3
C
60
; some of the earlier results are substantiated, while others are slightly modified.