Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio-Based Molecular Dynamics Study

Abstract

Although being crucial for GHz and THz applications, the ferroelectric response to ultrafast field stimuli is so far not well understood. We utilize ab initio based molecular dynamics simulations to analyze the ultrafast response of 180 • domain walls in the prototypical ferroelectric material BaTiO3. We reveal an initial acceleration of the domain wall up to 200% by non-equilibrium dipole switching and the equilibration to the steady-state by transient negative capacitance. Our detailed analysis reveals that the latter is a result of excess charge formation by switched local dipoles with low correlation. In addition, we suggest a relation between average bound charge and spacial dipoles distribution which can be used for statistical analyses of ferroelectric materials.

Interplay of domain structure and phase transitions: theory, experiment and functionality

“…the overall piezoelectric response to an external stimulus X, such as pressure is given as d = d init + αX with d init the reversible piezoelectric response and α a measure for irreversibility of the response [430,431]. Key property for the utilization of extrinsic responses in applications are thus the domain wall mobility [157,432,433] and the fundamental understanding and control of pinning centers [363,429,434].…”