TimeMan Seminar : Anna GRÜNEBOHM

Interplay of domain structure, phase transitions and functional responses in ferroelectric BaTiO₃

Anna Grünebohm

Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, Germany

Domain walls and phase boundaries are fundamental ingredients of ferroelectrics and govern their functional properties important for applications ranging from frequency conversion, energy harvesting, electrocaloric cooling and piezoelectric actuation to data storage. Although both interfaces have been studied for decades, often only a phenomenological macroscopic understanding has been established and recent studies reveal unexpected microscopic properties [1].

In this talk I will discuss how domain walls in the tetragonal and orthorhombic phases of BaTiO₃ may improve the functional properties in films with strain gradients [2] and reduce thermal hysteresis of phase transitions [3]. Furthermore, I will discuss our recent findings on the field-coupling of 180° domain walls [4].

All results have been obtained by ab-initio based molecular dynamics simulations [2].

Literature

[1] Interplay of domain structure and phase transitions:theory, experiment and functionality, Anna Grünebohm, Madhura Marathe, Ruben Khachaturyan, Raphael Schiedung, Doru C. Lupascu, and Vladimir V. Shvartsman, topical review J. Phys. Cond. matter. (2021)

[2] Temperature-independent giant dielectric response in transitional BaTiO₃ thin films, A. S. Everhardt, T. Denneulin, A. Grünebohm, Y.-T. Shao, P. Ondrejkovic, S. Zhou, N. Domingo, G. Catalan, J. Hlinka, J.-M. Zuo, S. Matzen and B. Noheda, , Appl. Phys. Rev. 7, 011402 (2020).

[3] Impact of domains on the orthorhombic-tetragonal transition of BaTiO₃: An ab initio study, Phys. Rev. Mater. 4, 114417, (2020)

[4] Domain wall acceleration by ultrafast field ramping and non-equilibrium dipoles dynamics: an ab initio based molecular dynamics study, Ruben Khachaturyan, Aris Dimou and Anna Grünebohm, https://arxiv.org/abs/2109.10062 (2021)

[5] Nishimatsu et al, Phys. Rev. B 78, 104104, 2008, Tinte et al. J. Phys. Condens. Matter 16, 3495, (2004).