Dresden 2006 – wissenschaftliches Programm

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DF: Dielektrische Festkörper

DF 1: Internal Symposium “Integrated Electroceramic Functional Structures”

DF 1.8: Vortrag

Montag, 27. März 2006, 12:10–12:30, M{\"U}L Elch

Polarisation-induced Functionality at Ferroelectric Surfaces — •Sibylle Gemming, Walter Alsheimer, Regina Ermrich, and Gotthard Seifert — Physikalische Chemie und Elektrochemie, TU Dresden, D-01062 Dresden.

Density-functional investigations on titanate-based ceramics have confirmed that the rich defect chemistry of these materials strongly influences the structural, electronic, and elastic properties of the bulk phases and at surfaces. Strong structural relaxations at stepped titanate (10n) surfaces were obtained, which can compete with the ferroelectric distortion. The electronic structure does not differ quantitatively from the bulk properties, and no edge-specific states inside the band gap of the bulk compound are induced. On the other hand, the electric field above a stepped surface differs from the one above a planar surface at distances, which are typical in adsorbate-substrate systems. Thus, the prereqisites for a polarisation-driven self-organisation of field-sensitive molecules on polar surfaces are given. A screening of several molecule classes revealed the thiophene series as promising candidates.