Intrinsic ferroelectric switching from first principles.

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Domain walls influence ferroelectric properties like dielectric, piezoelectric, and pyroelectric responses.
• Domain-wall motion is critical for polarization switching, observed as hysteresis loops in ferroelectric materials.
• Current models often rely on defect-driven pinning, leading to sample-dependent behavior and hindering theoretical prediction.

Purpose of the Study:

• To develop a universal analytical model for domain wall dynamics in ferroelectrics.
• To connect microscopic, first-principles calculations with macroscopic, finite-temperature properties.
• To enable accurate prediction of ferroelectric material properties for device design and discovery.

Main Methods:

• Molecular dynamics simulations of 90° domain walls in lead titanate (PbTiO3).
• Development of a nucleation-and-growth-based analytical model.
• First-principles calculations to predict temperature and frequency dependence of hysteresis loops and coercive fields.

Main Results:

• A simple, universal model for domain wall dynamics was constructed, applicable to various ferroelectrics.
• The intrinsic temperature and field dependence of domain-wall velocity was characterized, showing nonlinear creep and depinning regions.
• Predicted coercive fields showed good agreement with experimental data for ceramics and thin films.

Conclusions:

• Ferroelectric switching is largely governed by intrinsic domain-wall motion, even without defects.
• The developed model provides an efficient framework for predicting and optimizing ferroelectric material properties.
• This work bridges the gap between theoretical calculations and experimental observations, facilitating materials discovery.