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Title: Upper critical field reaches 90 tesla near the Mott transition in fulleride superconductors

Controlled access to the border of the Mott insulating state by variation of control parameters offers exotic electronic states such as anomalous and possibly high-transition-temperature (T c) superconductivity. The alkali-doped fullerides show a transition from a Mott insulator to a superconductor for the first time in three-dimensional materials, but the impact of dimensionality and electron correlation on superconducting properties has remained unclear. Here we show that, near the Mott insulating phase, the upper critical field H c2 of the fulleride superconductors reaches values as high as ~90 T—the highest among cubic crystals. This is accompanied by a crossover from weak- to strong-coupling superconductivity and appears upon entering the metallic state with the dynamical Jahn–Teller effect as the Mott transition is approached. Lastly, these results suggest that the cooperative interplay between molecular electronic structure and strong electron correlations plays a key role in realizing robust superconductivity with high-T c and high-H c2.
 [1] ;  [2] ;  [3] ; ORCiD logo [4] ;  [3] ;  [5] ;  [6] ; ORCiD logo [4] ;  [7]
  1. Kyoto Univ., Kyoto (Japan)
  2. Univ. of Tokyo, Tokyo (Japan)
  3. Durham Univ., Durham (United Kingdom)
  4. Tohoku Univ., Sendai (Japan)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  6. Univ. of Liverpool, Liverpool (United Kingdom)
  7. Univ. of Tokyo, Tokyo (Japan); RIKEN Center for Emergent Matter Science (CEMS), Saitama (Japan)
Publication Date:
Report Number(s):
Journal ID: ISSN 2041-1723
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; High Magnetic Field Science; Fulleride Superconductors Upper Critical Field
OSTI Identifier: