Thermodynamics of nanodomain formation and breakdown in Scanning Probe Microscopy: Landau-Ginzburg-Devonshire approach

TL;DR

This paper uses a Landau-Ginzburg-Devonshire model to analyze the thermodynamics of nanodomain formation and breakdown in ferroelectric materials under scanning probe microscopy, providing insights into polarization behavior and domain stability.

Contribution

It introduces a detailed phenomenological approach to understand tip-induced nanodomain formation, including polarization distribution and electrostatic fields, aligning theoretical predictions with experimental observations.

Findings

Calculated coercive biases match experimental data.

Identified the microscopic origin of tip-induced domain elongation.

Demonstrated local domain breakdown mechanisms in thin ferroelectric films.

Abstract

Thermodynamics of tip-induced nanodomain formation in scanning probe microscopy of ferroelectric films and crystals is studied using the Landau-Ginzburg-Devonshire phenomenological approach. The local redistribution of polarization induced by the biased probe apex is analyzed including the effects of polarization gradients, field dependence of dielectric properties, intrinsic domain wall width, and film thickness. The polarization distribution inside subcritical nucleus of the domain preceding the nucleation event is very smooth and localized below the probe, and the electrostatic field distribution is dominated by the tip. In contrast, polarization distribution inside the stable domain is rectangular-like, and the associated electrostatic fields clearly illustrate the presence of tip-induced and depolarization field components. The calculated coercive biases of domain formation are in a good agreement with available experimental results for typical ferroelectric materials. The microscopic origin of the observed domain tip elongation in the region where the probe electric field is much smaller than the intrinsic coercive field is the positive depolarization field in front of the moving counter domain wall. For infinitely thin domain walls local domain breakdown through the sample depth appears. The results obtained here are complementary to the Landauer-Molotskii energetic approach.