title: Superconductivity in the Graphite Intercalation Compound BaC(6).
abstract: Among many two-dimensional (2D) high T(C) superconductors, graphite intercalation compounds (GICs) are the most famous intercalation family, which are classified as typical electron-phonon mediated superconductors. We show unambiguous experimental facts that BaC(6), the superconductivity of which has been missing for many years so far among various alkaline earth metal (Ca, Sr, and Ba) intercalted GICs, exhibits superconductivity at T(C)=65  mK. By adding this finding as the additional experimental point, a complete figure displaying the relationship between T(C) and interlayer distance (d) for GICs is now provided, and their possible superconducting mechanisms raised so far are revisited. The present study settles a long-running debate between theories and experiments on the superconductivity in the first stage GICs.
authors.affiliation: WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Heguri
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kawade
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Fujisawa
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamaguchi
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sumiyama
authors.affiliation: WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.|Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Tanigaki
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Mototada
authors.initials: M
authors.lastname: Kobayashi