Large energy gaps in CaC{sub 6} from tunneling spectroscopy : possible evidence of strong-coupling superconductivity.

Journal Article · Sat Dec 01 00:00:00 EST 2007 · Phys. Rev. B

DOI:https://doi.org/10.1103/PhysRevB.76.220502· OSTI ID:1000678

Kurter, C; Ozyuzer, L; Mazur, D; Zasadzinski, J F; Rosenmann, D; Claus, H; Hinks, D G; Gray, K E

Tunneling in CaC{sub 6} crystals reproducibly reveals superconducting gaps {Delta} of 2.3 {+-} 0.2 meV that are {approx}40% larger than reported earlier. In an isotropic s-wave scenario, that puts CaC{sub 6} into the class of very strongly coupled superconductors, since 2{Delta}/kT{sub c}-4.6, implying that soft Ca phonons are primarily involved in the superconductivity. This conclusion explains the relatively large Ca isotope effect found recently for CaC{sub 6}, but it could also signal a strong anisotropy in the electron-phonon interaction.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 1000678
• Report Number(s): ANL/MSD/JA-68661; TRN: US1100162
• Journal Information: Phys. Rev. B, Vol. 76, Issue Dec. 2007
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANISOTROPY
ENERGY GAP
ISOTOPE EFFECTS
PHONONS
SPECTROSCOPY
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TUNNELING