Modiffied Schottky emission to explain thickness dependence and slow depolarization in BaTiO$_3$ nanowires

TL;DR

This paper presents a comprehensive physical model combining quantum tunneling, Schottky emission, and temperature effects to explain depolarization in ultrathin BaTiO$_3$ nanowires, aligning well with experimental observations.

Contribution

It introduces an improved tunneling-Schottky emission model that explains thickness and temperature dependence of depolarization in ferroelectric nanowires, validated by experimental data.

Findings

Depolarization results from charge leakage at surface adsorbates.

The model accurately simulates experimental depolarization rates.

The approach predicts retention time and leakage currents in ferroelectric materials.

Abstract

We investigate the origin of the depolarization rates in ultrathin adsorbate-stabilized ferroelectric wires. By applying density functional theory calculations and analytic modeling, we demonstrate that the depolarization results from the leakage of charges stored at the surface adsorbates, which play an important role in the polarization stabilization. The depolarization speed varies with thickness and temperature, following several complex trends. A comprehensive physical model is presented, in which quantum tunneling, Schottky emission and temperature dependent electron mobility are taken into consideration. This model simulates experimental results, validating the physical mechanism. We also expect that this improved tunneling-Schottky emission model could be applied to predict the retention time of polarization and the leakage current for various ferroelectric materials with different thicknesses and temperatures.