title: Optimized unconventional superconductivity in a molecular Jahn-Teller metal.
abstract: Understanding the relationship between the superconducting, the neighboring insulating, and the normal metallic state above T c is a major challenge for all unconventional superconductors. The molecular A3C60 fulleride superconductors have a parent antiferromagnetic insulator in common with the atom-based cuprates, but here, the C60 (3-) electronic structure controls the geometry and spin state of the structural building unit via the on-molecule Jahn-Teller effect. We identify the Jahn-Teller metal as a fluctuating microscopically heterogeneous coexistence of both localized Jahn-Teller-active and itinerant electrons that connects the insulating and superconducting states of fullerides. The balance between these molecular and extended lattice features of the electrons at the Fermi level gives a dome-shaped variation of T c with interfulleride separation, demonstrating molecular electronic structure control of superconductivity.
authors.affiliation: Department of Chemistry, Durham University, Durham DH13LE, UK.
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Zadik
authors.affiliation: Department of Chemistry, Durham University, Durham DH13LE, UK.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takabayashi
authors.affiliation: Department of Chemistry, Durham University, Durham DH13LE, UK. ; Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.
authors.forename: Gyöngyi
authors.initials: G
authors.lastname: Klupp
authors.affiliation: Department of Chemistry, Durham University, Durham DH13LE, UK.
authors.forename: Ross H
authors.initials: RH
authors.lastname: Colman
authors.affiliation: Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
authors.forename: Alexey Y
authors.initials: AY
authors.lastname: Ganin
authors.affiliation: Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
authors.forename: Anton
authors.initials: A
authors.lastname: Potočnik
authors.affiliation: Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
authors.forename: Peter
authors.initials: P
authors.lastname: Jeglič
authors.affiliation: Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
authors.forename: Denis
authors.initials: D
authors.lastname: Arčon
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Matus
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Kamarás
authors.affiliation: Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kasahara
authors.affiliation: Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Iwasa
authors.affiliation: European Synchrotron Radiation Facility, 38043 Grenoble, France.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Fitch
authors.affiliation: Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohishi
authors.affiliation: European Synchrotron Radiation Facility, 38043 Grenoble, France.
authors.forename: Gaston
authors.initials: G
authors.lastname: Garbarino
authors.affiliation: RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rosseinsky
authors.affiliation: Department of Chemistry, Durham University, Durham DH13LE, UK. ; World Premier International-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan. ; Japan Science and Technology Agency, ERATO Isobe Degenerate π-Integration Project, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Kosmas
authors.initials: K
authors.lastname: Prassides
keywords: Jahn-Teller effect; Metal-insulator transitions; Strong correlations; superconductivity