Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 6: Electronic Structure and Spectroscopy I
CPP 6.10: Talk
Monday, March 27, 2006, 17:00–17:15, ZEU 114
Anisotropy of the transport mechanisms in organic quasi 1D conductors — •David Saez de Jauregui and Elmar Dormann — Physikalisches Institut, Universität Karlsruhe (TH), D-76128 Karlsruhe
Arene radical cation salts (rcs) are synthetic metals
consisting of polycyclic aromatic hydrocarbons (i.e. naphthalene, fluoranthene, pyrene or perylene) and
inorganic complex anions (i.e. PF6, AsF6 or SbF6) . Due to a π-orbital overlap of the arene molecules
and a not completely filled conduction band the rcs are quasi-one dimensional conductors.
They perform a Peierls transition between a metallic high
temperature phase with a pseudo-gap caused by fluctuations
and charge density ground.
These rcs provide excellent model systems for investigations of the transport dynamics, because both
the electronic charge as well as the electron spin motion can be detected.
Using microwave conductivity
measurements and X-band-pulse-ESR techniques with applied static
field gradients the electron charge motion and the electron spin diffusion were examined for
different orientations and a broad temperature regime below and above the semiconductor-metal phase transition.
This was done for rcs with different paramagnetic defect concentrations.
The influence of defects is a decrease of the anisotropic behavior of the organic conductors.
The real "intrinsic"
anisotropy of the electrical conductivity and the spin diffusion coefficient must be derived by extrapolation to
vanishing defect concentration.