Pressure on charged domain walls and additional imprint mechanism in ferroelectrics

TL;DR

This paper analyzes how free charges influence the local pressure on charged ferroelectric domain walls, revealing that charge compensation can significantly reduce wall mobility and introduce an additional imprint mechanism affecting ferroelectric switching.

Contribution

It derives a general formula for the pressure on charged domain walls considering free charge compensation, highlighting its impact on domain wall mobility and ferroelectric switching.

Findings

Free charge compensation reduces the pressure on domain walls.

Charge compensation can lead to nonlinear effects influencing wall behavior.

Reduced pressure affects the switching properties of ferroelectric materials.

Abstract

The impact of free charges on the local pressure on a charged ferroelectric domain wall produced by an electric field has been analyzed. A general formula for the local pressure on a charged domain wall is derived considering full or partial compensation of bound polarization charges by free charges. It is shown that the compensation can lead to a very strong reduction of the pressure imposed on the wall from the electric field. In some cases this pressure can be governed by small nonlinear effects. It is concluded that the free charge compensation of bound polarization charges can lead to substantial reduction of the domain wall mobility even in the case when the mobility of free charge carriers is high. This mobility reduction gives rise to an additional imprint mechanism which may play essential role in switching properties of ferroelectric materials. The effect of the pressure reduction on the compensated charged domain walls is illustrated for the case of 180-degree ferroelectric domain walls and of 90-degree ferroelectric domain walls with the head-to-head configuration of the spontaneous polarization vectors.