Regensburg 2013 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 3: Dielectric surfaces and interfaces

DF 3.1: Talk

Monday, March 11, 2013, 10:30–10:50, H11

First principles simulation of a moving longitudinal domain wall in PbTiO₃ — •Kourosh Rahmanizadeh, Gustav Bihlmayer, and Stefan Blügel — Peter Grünberg Institut (PGI-1) & Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

In ferroelectrics, the formation of domain walls can compensate the surface charge, release elastic strain and lower the free energy of the crystal. However, 180^∘ head-to-head domain walls are energetically costly due to electrostatic repulsion of charges at the interface. It is possible to reduce the electrostatic energy at the longitudinal domain wall by including electron donors / acceptors.

We carried out density functional theory calculations based on the full-potential linearized augmented planewave (FLAPW) method as implemented in the FLEUR code (www.flapw.de) for simulating domain walls in PbTiO₃. To stabilize these walls, we introduce effective Ti and O vacancies for accepting and donating electrons.

We modeled the growth of domains with different configurations of the vacancies. For each configuration, the structures were optimized. We also investigated the pinning strength of domain walls in PbTiO₃. To this end, we applied external electric fields ranging up to 9×10⁷ V/cm to the simulated structures, monitoring the evolution of the total energy.

Financial support of the EU grant NMP3-LA-2010-246102 (IFOX) is gratefully acknowledged.