Daluram Yadav¹, Nishchhal Yadav¹, Sanjay K. Ghosh^1,

The electron pairing mechanism leading to superconducting state in K₃C₆₀ fullerenes is explored within the framework of strong coupling theory. The intercage interactions between C₆₀ cages and expansion of lattice due to the intercalation of K atoms are investigated using the nearest neighbor interactions. The renormalized Coulomb repulsive parameter μ* and the electron phonon coupling strength λ are obtained for the intermolecular phonon frequency ω_er, keeping in mind that the free electrons in lowest molecular orbital are coupled with intermolecular phonons. T_c is then estimated as 5 K, which is much lower as compared with the reported value. The electrons also couple with the intramolecular phonons then T_c enhances to 22 K. In this approach the carbon isotope effect exponent, the energy gap ratio, effect of pressure and volume on T_c is calculated which support the superconducting state.

fullerenes, intermolecular phonons, intramolecular phonons, transition temperature, carbon isotope effect, energy gap ratio