Optimized unconventional superconductivity in a molecular Jahn-Teller metal.
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.
['Zadik|Ruth H|RH|', 'Takabayashi|Yasuhiro|Y|', 'Klupp|Gyöngyi|G|', 'Colman|Ross H|RH|', 'Ganin|Alexey Y|AY|', 'Potočnik|Anton|A|', 'Jeglič|Peter|P|', 'Arčon|Denis|D|', 'Matus|Péter|P|', 'Kamarás|Katalin|K|', 'Kasahara|Yuichi|Y|', 'Iwasa|Yoshihiro|Y|', 'Fitch|Andrew N|AN|', 'Ohishi|Yasuo|Y|', 'Garbarino|Gaston|G|', 'Kato|Kenichi|K|', 'Rosseinsky|Matthew J|MJ|', 'Prassides|Kosmas|K|']
superconductivity Jahn-Teller effect Metal-insulator transitions Strong correlations