title: A new way to synthesize superconducting metal-intercalated C60 and FeSe.
abstract: Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc's, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors.
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Takahei
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Tomita
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Itoh
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Keishi
authors.initials: K
authors.lastname: Ashida
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nishimoto
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.|Research Centre of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kudo
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.|Research Centre of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Nohara
authors.affiliation: Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.|Research Centre of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530, Japan.|Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kubozono
authors.affiliation: Department of Physics, Okayama University, Okayama 700-8530, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kambe