Structural and Electronic Properties of Selected Fulleride Salts

Abstract

The study of strongly correlated electron systems is at the forefront of contemporary condensed matter research because such materials, which include transition metal oxides (colossal magnetoresistive manganites, high-T _c cuprates) and intermetallic heavy fermion systems, display remarkable electronic properties that challenge existing theory for satisfactory explanations. The interplay between charge, lattice, orbital and magnetic degrees of freedom in all these systems can be tuned sensitively both physically (varying an external parameter like pressure or magnetic field) and chemically (changing the chemical composition). A prominent branch of strongly correlated electron systems is the family of metal-intercalated fullerides, which display superconductivity at temperatures as high as 40 K. In this chapter, we discuss the structures and electronic and magnetic properties of selected fullerene-based architectures focusing on ammonia co-intercalated metal fullerides which are located at the boundaries of metal-insulator transitions, on alkaline-earth fullerides which deviate strongly from rigid band behaviour and on rare-earth fullerides which present unique opportunities based on the coupling between the lanthanide and fulleride electronic structures.