Smearing of phase transition due to surface effect in ferroelectric nanostructures

TL;DR

This paper investigates how surface effects in ferroelectric nanostructures modify boundary conditions, leading to suppression of phase transitions and washing out anomalies, aligning with experimental observations.

Contribution

It introduces a modified boundary condition model that accounts for surface defect fields affecting phase transition behavior in ferroelectric nanostructures.

Findings

Surface defect fields suppress second order phase transitions.

Anomalies in response are washed out due to surface effects.

Modified boundary conditions better match experimental results.

Abstract

The boundary conditions, customarily used in the Landau-type approach to ferroelectric thin films and nanostructures, have to be modified to take into account that a surface of a ferroelectric (FE) is a defect of a ``field'' type. The surface (interface) field is coupled to a normal component of polarization and, as a result, the second order phase transitions are generally suppressed and anomalies in response are washed out, as observed experimentally.