Anomalous isotope effects of fulleride superconductors

W. Fan

Anomalous isotope effects of fulleride superconductors

Superconductivity 2008-11-25 v1 Materials Science

Authors: W. Fan

Abstract

The numerical calculations of the standard Eliashberg-Nambu strong coupling theory and a formula of isotope effect derived in this paper provide direct evidences that an-harmonic vibrations of lattice enhance isotope effect with anomalous coefficient $\alpha>1/2$ . The results in this paper explain very well the wide distributed $\alpha$ values for the samples with different ratios of substitutions of $^{12}$ C by $^{13}$ C of fulleride superconductor Rb $_{3}$ C $_{60}$ . The calculations of isotope effects indicate that the intra-molecule radial modes have more important contributions to superconductivity than the intra-molecule tangential modes with higher phonon frequencies

Keywords

fulleride superconductors isotope effect Eliashberg-Nambu theory anharmonic lattice vibrations phonon modes

Cite

@article{arxiv.0811.3813,
  title  = {Anomalous isotope effects of fulleride superconductors},
  author = {W. Fan},
  journal= {arXiv preprint arXiv:0811.3813},
  year   = {2008}
}

Comments

Accepted by International of Modern Physics B (13pages, 2eps figure)

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