Abstract
Terahertz reflectance spectra of the Ca-intercalated graphite reveal a superconducting gap below 11 K. The gap signature lacks a sharp onset to full reflectivity at but rather shows a distribution of gap values consistent with an anisotropic gap. The experimental data were successfully fitted to the gap distribution obtained from density-functional calculations of Sanna et al. [Phys. Rev. B 75, 020511(R) (2007)]. The temperature dependence of the superconducting gap is characteristic for a BCS type superconductor.
- Received 16 April 2008
DOI:https://doi.org/10.1103/PhysRevB.78.041404
©2008 American Physical Society