Seminars Archive
Serena Margadonna
Abstract
Monday, February 28, 2000, 10:00
Seminar Room, ground floor, Building "T"
Sincrotrone Trieste, Basovizza
Current issues in fullerene-based superconductors.
Serena Margadonna
(School of Chemistry, Physics and Environmental Science, University
of Sussex,
Falmer, UK)
ABSTRACT
The present seminar will deal with some of the recent advances in research
on fullerene solids. Emphasis will be placed on superconducting
and magnetic fullerene derivatives. These include solids characterised
by: (i) small interfullerene spacings - in these cases, the superconducting
primitive cubic phases of quaternary sodium fullerides, Na2(A,A`)C60 and
of ternary lithium fullerides, LixCsC60 compete in stability with the formation
of quasi-one-dimensional bridged C603- polymeric structures; in particular,
the Li phases also allow fine tuning of the doping level of the conduction
band through the variation of the Li content, x. Finally, synthesis of
alkaline earth, AExC60 fullerides allows the population of the (LUMO+1)-derived
band. The occurrence of metallic and superconducting compositions will
be discussed. (ii) large interfullerene spacings - in this case, superconductivity
is suppressed and magnetic origin effects dominate; for instance, the ammoniated
alkali fulleride, (NH3)K3C60 orders antiferromagnetically at TN~40 K- providing
a connection with the established phenomenology in high-Tc and organic
superconductors.
