Inhaltszusammenfassung

Organic conductors are a large class of strongly-correlated low-dimensional materials, exhibiting a variety of fundamental phenomena. Some of these materials are close to wide implementation in industry as components for electronics and alternative power engineering. All of the organic conductors are interesting for fundamental research because of their variety of phenomena and because these materials do not occur naturally. The present work addresses the fundamental questions of electronic s...Organic conductors are a large class of strongly-correlated low-dimensional materials, exhibiting a variety of fundamental phenomena. Some of these materials are close to wide implementation in industry as components for electronics and alternative power engineering. All of the organic conductors are interesting for fundamental research because of their variety of phenomena and because these materials do not occur naturally. The present work addresses the fundamental questions of electronic structure investigations and their correlation with other known properties of the organic materials. Following this goal, the phase characterization of the (DOEO)4[HgBr4]·TCE organic charge transfer complex was performed based on spectroscopic data (X-ray absorption and photoelectron spectroscopy using soft and hard X-rays from synchrotron sources) compared to resistivity, magnetic susceptibility and electron spin resonance. Furthermore, observed changes of the electronic structure of the unoccupied states in TTF-TCNQ organic metal crystals, which develop with cooling, suggest band gap opening at the Peierls transitions. Additionally, pre-transitional structural fluctuation of the acceptor (pyramidalization of TCNQ) was observed. Two more charge transfer organic complexes were investigated in scope of the present work using X-ray absorption: DTBDT-TCNQ and DTBDT-F4TCNQ. Comparison of the X-ray absorption spectra with theoretical calculations (performed in the group of R. Valentí, University of Frankfurt (M)) reveals and quantifies the strong effect of the core-hole that leads to a reassignment of the X-ray absorption signals.» weiterlesen» einklappen

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DDC Sachgruppe:
Naturwissenschaften