Flexoelectric Fracture-Ratchet Effect in Ferroelectrics.

Area of Science:

• Materials Science
• Solid Mechanics
• Condensed Matter Physics

Background:

• Crack propagation generates significant strain gradients.
• Strain gradients are a primary source of gradient-induced polarization, known as flexoelectricity.
• Flexoelectric effects are particularly pronounced at crack fronts.

Purpose of the Study:

• To investigate the influence of flexoelectricity on crack propagation dynamics in piezoelectric materials.
• To determine if flexoelectricity introduces asymmetry in crack growth.
• To highlight the necessity of incorporating flexoelectricity into fracture models for polar materials.

Main Methods:

• Theoretical analysis of crack propagation in piezoelectric media.
• Modeling the interplay between strain gradients and polarization.
• Simulating crack behavior under varying orientations relative to the piezoelectric polar axis.

Main Results:

• Flexoelectricity was demonstrated to influence crack propagation.
• Crack growth was found to be either assisted or hindered based on its alignment with the piezoelectric polar axis.
• This demonstrates a clear asymmetry in crack propagation behavior.

Conclusions:

• Fracture physics in polar materials is inherently asymmetric due to flexoelectric effects.
• Flexoelectricity must be included in comprehensive models of fracture mechanics for piezoelectric materials.
• The findings open new avenues for controlling crack propagation through material polarization.