Berlin 2008 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 11: Dielectric and ferroelectric thin films and nanostructures I
DF 11.9: Vortrag
Mittwoch, 27. Februar 2008, 16:40–17:00, EB 107
A combined first principles and electron-holographic aproach to domain boundaries in (multi)ferroic materials — •Axel Rother1, Nicola Spaldin2, and Hannes Lichte1 — 1Institute for Structural Physics, TU Dresden, 01062, Germany — 2Materials Department, University of California, Santa Barbara, CA 93106
Domain boundaries in ferroic materials deviate from the bulk in both the structural and electronic properties. Their presence in the material influences the total energy of the system as well as the dynamic properties, for instance during polarization switching. We report on a combined Density Functional Theory and Electron Holographic approach on domain boundaries in multiferroic BiFeO3, ferroelectric BaTiO3 and other (multi-)ferroic materials. Our model systems extend over different domain walls with respect to material composition and angular change and encompass between 50-120 atoms. The calculations were performed within VASP, a package for DFT using pseudopotentials and a plane wave basis set, particularly suited for such big systems. The calculations reveal the details of charge and structure modulation on the boundary, including the formation of dipole layers and a change in the magnetic behaviour in case of BiFeO3. Electron holographic measurements support the findings of the calculations by measuring dipole layers and charge modulations on the domain boundaries.