Electron-phonon Pairing Mechanism for Superconductivity in K₃C₆₀ Fullerides

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

¹School of Studies in Physics, Vikram University, Ujjain, India

Cite this paper:
Daluram Yadav, Nishchhal Yadav and Sanjay K. Ghosh. Electron-phonon Pairing Mechanism for Superconductivity in K₃C₆₀ Fullerides. Journal of Materials Physics and Chemistry. 2013; 1(2):9-18. doi: 10.12691/jmpc-1-2-1

Abstract

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.

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

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