Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 30: POSTER: Chemical physics
CPP 30.64: Poster
Dienstag, 8. März 2005, 16:30–18:30, Poster TU D
Anisotropy of electron spin diffusion in organic quasi-1D-conductors — •Armin Warth, David Saez de Jauregui, Stefan Matejcek, and Elmar Dormann — Physikalisches Institut, Universität Karlsruhe(TH),
The organic conductors (Fluoranthen)2PF6 and (Perylen)2AsF6 ×
2/3 THF
belong to the family of the so called arene
radical cation salts and provide good model systems for the investigating the one-dimensional
electron dynamics. Like other representatives of the organic quasi-1D-conductors a
Peierls-transition can be observed
in both conductors
but at different temperatures.
Using X-band-pulse-ESR techniques with optimized static field
gradients the electron spin diffusion was examined for different orientations and a
broad temperature regime
below and above the semiconductor-metal phase transition. These analyzes were focused on the
determination
of the electron spin motion perpendicular to the molecular
stacking axis a, where
the diffusion seems to be dominated by a conduction electron hopping process.
The results show
the highly
anisotropic character of the systems comparing parallel and
perpendicular to stack
diffusion. By irradiating a fluoranthen crystals with high energetic protons, the concentration of
localized paramagnetic defects could be increased and the anisotropy decreased by about two orders
of magnitude.