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Multistep polarization switching on orthorhombic domain walls: a molecular dynamic study

Anna Grünebohm, Ruhr-Universität Bochum, Bochum, Germany

Aris Dimou, Ruhr-Universität Bochum, Bochum, Germany

Ruben Khachaturyan, Ruhr-Universität Bochum, Bochum, Germany

Sheng-Han Teng, Ruhr-Universität Bochum, Bochum, Germany

Pierre Hirel, Université de Lille, Villeneuve d’Ascq, France

Time & Place
  • Date: 07.02.2023
  • Time:
  • Place: Fundamental Physics of Ferroelectrics and Related materials 2023, Colarado School of Mines, Golden, USA

Abstract

Ferroelectric switching is the key property for a wide range of applications, ranging from actuators to memory devices. In spite of its fundamental relevance the ferroelectric switching process and its coupling to the microstructure is still not fully understood [1].

In this contribution we combine density functional theory and molecular dynamics simulations to study the microscopic processes governing the field-induced domain wall motion in (Sr,Ba)TiO3

Excitingly, we find that fast field changes may boost the wall velocity by non- equilibrium switching of local dipoles [2], see Figures (a--c). With time these dipoles switch back and the domain wall motion reaches its steady state. The dynamics of the wall can be considerably modified by point defects and inhomogeneities. For example, Sr-rich regions strained by a surrounding Ba-rich matrix increase the energy barrier for the wall motion, see Figures (d)—(e).

In the orthorhombic phase, local non-180o switching of dipoles on the traveling walls results in transient local Bloch type walls and dipole vortices.

References
[1] A. Grünebohm et al., J. Phys.: Condens. Matt. 34, 073002 (2021).
[2] R. Khachaturyan et al. Phys. Stat. Solidi RRL 16, 2200038 (2022).
[3] A. Dimou et al., Phys. Rev. B 106, 094104 (2022).

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