ELECTRON-PHONON INTERACTIONS AND SUPERCONDUCTIVITY IN K3C60

Using electronic states and phonon states from first-principles calculations on K3C60 to evaluate the quantities in the McMillan equation, we examine the effects of both electron-phonon dynamic charge coupling (Q) and Jahn-Teller coupling (JT) on various superconducting properties, including T(c), DELTAT(c) (the shift of T(c) for 1 GPa pressure), alpha(C) (the isotope exponent for C-12 --> C-13), and alpha(K) (the isotope exponent for K-39 --> K-41). All quantities including electron-phonon coupling are evaluated (without modification) directly from theory, except for the screening length between conducting electrons and ions, R(SC). With R(SC) = 0.8 - 1.0 angstrom, we find that the calculated properties, T(c), DELTAT(c), and alpha(C), are all in good agreement with experimental measurements. We find that the superconducting properties depend critically upon the synergy between Q and JT coupling.