Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 38: Multiferroics
MA 38.12: Talk
Thursday, March 26, 2009, 18:15–18:30, HSZ 103
First principle calculations of domain boundaries in muliferroic BiFeO3 — •Axel Lubk1, Nicola Spaldin2, Sibylle Gemming3, and Hannes Lichte1 — 1Institute for Structure Physics, Technische Universität Dresden, Germany — 2Materials Department, University of California, Santa Barbara, USA — 3Institute of Ion Beam Physics and Materials Research,Forschungszentrum Dresden-Rossendorf, Germany
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, the band structure and the magnetic and electric polarization. We report on a Density Functional Theory (DFT) approach within the Local Density Approximation on domain boundaries in multiferroic BiFeO3 (space group: R3c). Our model systems consist of the experimentally observed 71°, 109° and 180° domain walls. The calculations were performed within the DFT software VASP, incorporating standard pseudopotentials and a plane wave basis set. A complete electronic and ionic relaxation of the model structures has been performed to yield details of the charge and structure modulation at the boundary including the deformation of the Fe-centered oxygen octahedron, the formation of electric dipole layers leading to a jump in the electrostatic potential, band gap narrowing and a domain wall dependent modification of the small ferromagnetic effect present in BiFeO3.