Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 10: Focus Session: Ferroic Domain Walls III

DF 10.5: Vortrag

Mittwoch, 9. März 2016, 16:50–17:10, H25

Landau theory of domain walls revisited — •Wilfried Schranz — University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria

Domain walls and twin boundaries currently attract enormous attention, since they can host functional properties that are not present in the bulk crystal [1,2]. CaTiO3 is the first example, where it was succeeded in observing a ferroelectric polarization [2] inside a ferroelastic twin wall while the rest of the crystal remained centrosymmetric. There are many more examples demonstrating the application potential of functional domain walls in future information technologies. Modelling of functional twin walls ranges from ab-initio calculations [3] to phenomenological descriptions based on Ginzburg-Landau-Devonshire free energies [4]. The possibility of an electric polarization in ferroelastic twin walls was already predicted long time ago by V. Janovec [5,6], based on a group theoretical symmetry approach. In the present talk we show how we may use the layer-group approach of domain twins [7] to describe corresponding functional properties of domain walls.

Supported by the Austrian FWF (P28672-N36).

[1] Seidel, et al., R. Nature Materials 8, 229 Vol 34 (2009). [2] Van Aert, S., et al., Adv. Mater. 24, 523 (2012). [3] B. Meyer and D. Vanderbilt, Phys. Rev. B 65, 104111 (2002). [4] P. Marton, I. Rychetsky, and J. Hlinka, Phys. Rev. B 81, 144125 (2010). [5] V. Janovec, L. Richterová and J. Prívratská, Ferroelectrics 222, 73 (1999). [6] V. Janovec, W. Schranz, H. Warhanek and Z. Zikmund, Ferroelectrics 98, 171 (1989). [7] V. Janovec, Ferroelectrics 35, 105 (1981).