In this work, we have performed resonant photoemission studies of Ca-intercalated graphite superconductor CaC6. Using photon energy of the Ca 2p-3d threshold, the photoemission intensity of the peak at Fermi energy (EF) is resonantly enhanced. This result provides spectroscopic evidence for the existence of Ca 3d states at EF, and strongly supports that Ca 3d state plays a crucial role for the superconductivity of this material with relatively high Tc.
- Graphite intercalation compound
- Resonant photoemission spectroscopy