Perylene hexafluoroantimonate: Suppression of the Peierls transition by anion-chain disorder
Physikalisches Institut, Universität Karlsruhe (TH), 76128 Karlsruhe, Germany
2 Institut für Kristallographie, Universität Karlsruhe (TH), 76128 Karlsruhe, Germany
Published online: 15 March 1999
Crystal growth and X-ray structural analysis are reported for the new quasi-one-dimensional organic conductor perylene hexafluoroantimonate. Due to deviation from exact 4:3 stoichiometry and anion-chain disorder the three-dimensional Peierls transition is suppressed to temperatures below 30 K in spite of a molecular field transition temperature of 330 K. Anisotropy of the microwave conductivity exceeds 3000:1 at room temperature. Curie paramagnetic defects with comparatively small electron spin resonance line width predominate at low temperature. Thermally activated paramagnetic defects, giving rise to pronounced Overhauser shift, are separated in the 30-100 K range. They are explained by neutral Perylene intra-stack defects, whose concentration can be reduced by both aging and annealing. The angular and temperature dependence of the conduction electron spin resonance line is analysed in detail, exhibiting the influence of intra-stack dipole interaction growing with temperature. Restricted diffusion of the conduction electron spins with diffusion coefficient of about 6 cm2/s parallel to the stacking direction is detected by fixed gradient pulsed electron spin resonance at room temperature.
PACS: 61.65.+d – Specific structure of organic compounds / 72.80.Le – Organic semiconductors / 76.30.-v – Electron paramagnetic resonance and relaxation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999