Superconductivity and magnetism at and above 38K in molecular materials
Lead Research Organisation:
University of Liverpool
Department Name: Chemistry
Abstract
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People |
ORCID iD |
| Matthew Rosseinsky (Principal Investigator) |
Publications
Bacsa J
(2011)
Cation vacancy order in the K0.8+xFe1.6-ySe2 system: Five-fold cell expansion accommodates 20% tetrahedral vacancies
in Chemical Science
Chacón-Torres J
(2012)
De-intercalation process from Stage -1 to Stage -2 graphite intercalation compounds revisited
in physica status solidi (b)
Ganin AY
(2010)
Polymorphism control of superconductivity and magnetism in Cs(3)C(60) close to the Mott transition.
in Nature
Jeglic P
(2009)
Low-moment antiferromagnetic ordering in triply charged cubic fullerides close to the metal-insulator transition
in Physical Review B
Klupp G
(2012)
Dynamic Jahn-Teller effect in the parent insulating state of the molecular superconductor Cs3C60.
in Nature communications
Zhang J
(2018)
Reactivity of Solid Rubrene with Potassium: Competition between Intercalation and Molecular Decomposition.
in Journal of the American Chemical Society
| Description | We identified the first example of polymorphic (molecular packing) control of superconductivity by isolating both face-centred cubic and body-centred cubic variants of Cs3C60 (corresponding to two different packings of the spherical C60 molecule) by detailed manipulation of the synthesis conditions. This allowed us to demonstrate that the packing controlled the maximum superconducting transition temperature via the proximity of the materials to the metal-insulator transition, and also how the packing controlled the magnetic ground state that was in competition with superconductivity. This advance in materials synthesis permitted spectroscopic measurements of the electronic state of the triply charged C60 anion in both polymorphic materials in the insulating state that competes with superconductivity. These measurements revealed the importance of interaction between the electrons responsible for superconductivity and the vibrational motions of the C60 molecule itself in the Jahn-Teller effect. The observation of Jahn-Teller coupling both reveals the molecular origin of the electronic states in the insulating phases that are the parents of the superconductors and shows that when electron repulsions localise the electrons, the nature of their coupling with vibrations in the solid changes. This is key design information for future classes of superconducting material. |
| Exploitation Route | In the fundamental understanding of the mechanisms producing unconventional superconductivity - subsequent ab initio DFT/Eliashberg calculations have shown that Cs3C60 cannot operate via a conventional electron-phonon coupling mechanism in either polymorph, establishing it as an unconventional superconductor. In the design of new families of superconducting materials through the incorporation of molecular electronic structure features such as Jahn-Teller coupling shown to be involved in the new families of unconventional superconductors identified here. |
| Sectors | Digital/Communication/Information Technologies (including Software),Electronics,Energy |