WEB Investigation of a correlated nucleation and polarization kinetics in BaTiO3 by means ab initio based molecular dynamics simulationsWednesday (23.09.2020) 09:30 - 09:45 M: Modelling and Simulation 1 Part of:
The thorough understanding of polarization switching is important both from a scientific and application point of view. The process of polarization switching can be subdivided into nucleation and further nucleus growth. In a defect-free material, a domain wall (DW) may serve as a nucleation centre . In this contribution, we discuss the polarization reversal in BaTiO3 in presence of 180° domain walls. A detailed analysis of nuclei formation and further growth in- and out-of-DW plane are presented. It is known that polarization reversal has to be correlated in space to overcome the electrostatic/electromechanical barriers and form a viable nucleus . In our work, both temporal and spatial correlations of polarization components are studied and are related to an average electrostatic energy of a system. We find that a number of layers and cells is involved in the coherent switching at each particular polarization state.
To approach conditions of a real experiment, we increase an electric field within a finite amount of time. For our simulations, we used the feram code  to perform molecular dynamics simulations based on an effective Hamiltonian first introduced by Rabe and Vanderbid  allowing for efficient simulation of DW .
 Young-Han Shin et al., Nature 449, 881–884 (2007)
 Jie E. Zhou, at al., Journal of App. Physics 111, 02 (2012)
 A. Grünebohm et al., Appl. Phys. Lett. 107, 10 (2015)
 W. Zhong et al., Phys. Rev. B 52 (1995)