Intrinsic Mechanical Compliance of 90° Domain Walls in PbTiO_3

摘要

Functionality of domain walls and other topological defects in ferroelectricsis being widely investigated for applications in electronic devices. While theintrinsic electronic properties of a wall have been considered, its inherentmechanical properties remain explored very little, despite the fact that couplingbetween strain and polarization is prevalent in many of these materials. Herein,an in-depth study of variations in nanomechanical properties at 90° domainwalls and their adjacent domains in single-crystalline lead titanate (PbTiO_3) ispresented as a prototypical ferroelectric material using a combination of variousatomic force microscopy (AFM)-based methods. Considerable variations ofelastic moduli are found at 90° domain walls extending up to ～100 nm into thedomain areas. AFM nanoindentation also allows to extract local domain wallhardness and plastic and elastic deformation energies. These findings haveimplications for the design of ferroelectric domain wall functionality that incorporatesthe intrinsic elastic compliance of a domain wall.