Electrons and Phonons in YbC6
Abstract
Description
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.
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
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