Upper critical field reaches 90?tesla near the Mott transition in fulleride superconductors.

ABSTRACT: 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. 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.

SUBMITTER: Kasahara Y 

PROVIDER: S-EPMC5321754 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature