Alkali fullerides exhibit superconductivity with Tc's as high as 33 K at ambient pressure. The transition temperatures scale monotonically with unit cell size, an observation rationalized as arising from the modulation of the electronic density-of-states at the Fermi level, N(εF) by the interfullerene spacing, α. Deviations from this relationship leading to suppressed Tc's are apparent at small interfullerene spacings for sodium fullerides, Na2(A,Á)C60 and may be linked to the formation of quasi-one-dimensional bridged fulleride structures. Superconductivity is also suppressed at large interfullerene spacings for (NH3)K3C60 whence magnetic origin effects play an important role and provide a connection with the established phenomenology in high-Tc and organic superconductors.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering