Flexoelectric fracture-filter effect in ferroelectrics

TL;DR

This paper reveals that flexoelectric effects cause asymmetric crack propagation in ferroelectrics, impacting fracture behavior and enabling new applications in nanopatterning and device durability.

Contribution

It demonstrates that flexoelectricity induces crack propagation asymmetry in ferroelectrics, challenging traditional fracture symmetry assumptions and opening new avenues for material design.

Findings

Crack propagation is influenced by flexoelectric polarization depending on crack orientation.

Flexoelectricity causes asymmetry in fracture behavior of ferroelectric materials.

Implications for electromechanical fatigue and nanopatterning techniques.

Abstract

The propagation front of a crack generates large strain gradients and it is therefore a strong source of gradient-induced polarization (flexoelectricity). Herein, we demonstrate that, in piezoelectric materials, a consequence of flexoelectricity is that crack propagation will be helped or hindered depending on whether it is parallel or antiparallel to the piezoelectric polar axis. This means that the theory of fracture physics can no longer assume mechanical symmetry in polar materials. The discovery of fracture asymmetry also has practical repercussions for the electromechanical fatigue of ferroelectrics and piezoelectric transducers, as well enabling a new degree of freedom for crack-based nanopatterning.