The electronic structure and selected zone-center phonons in Yb graphite intercalation compound (YbC6) are investigated {theoretically} using density functional calculations and LDA+U approximation for Coulomb correlations in the f shell, and experimentally using angle-resolved photoemission. We find that both in LDA and LDA+U approach the Yb f states are fully occupied providing no evidence for mixed-valent behavior. The obtained theoretical results are in good agreement with photoemission experiments. The 4f states are considerably hybridized both with the Yb 5d and C 2p states resulting in a substantial admixture of Yb f at the Fermi level. Soft Yb phonons, given a noticeable presence of the Yb states at the Fermi level, are probably responsible for the superconductivity recently reported in YbC6.
@article{arxiv.cond-mat/0503650,
title = {Electrons and Phonons in YbC6},
author = {I. I. Mazin and S. L. Molodtsov},
journal= {arXiv preprint arXiv:cond-mat/0503650},
year = {2007}
}
Comments
For consistency, we post without any changes the manuscript as submitted to PRB on 3/17/2005; however, in meanwhile the key Ref.6 has been made available by the authors as cond-mat/0503570 and will be referred to as such in the future versions