Influence of layer defects on the damping in ferroelectric thin films

TL;DR

This paper investigates how structural defects like impurities, vacancies, and dislocations affect the damping of excitations in ferroelectric thin films, using a Green's function approach to analyze temperature, thickness, and interaction effects.

Contribution

It introduces a Green's function method for a modified Ising model to quantify defect-induced damping in ferroelectric thin films, aligning theoretical results with experimental data.

Findings

Defect layers significantly increase damping in ferroelectric films.

Damping depends on temperature, film thickness, and interaction strength.

Theoretical results agree with experimental observations.

Abstract

A Green's function technique for a modified Ising model in a transverse field is applied, which allows to calculate the damping of the elementary excitations and the phase transition temperature of ferroelectric thin films with structural defects. Based on an analytical expression for the damping function, we analyze its dependence on temperature, film thickness and interaction strength numerically. The results demonstrate that defect layers in ferroelectric thin films, layers with impurities or vacancies as well as layers with dislocations are able to induce a strong increase of the damping due to different exchange interactions within the defect layers. The results are in good agreement with experimental data for thin ferroelectric films with different thickness.