Enhanced Piezoelectric Response at Nanoscale Vortex Structures in Ferroelectrics.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The piezoelectric response quantifies a material's sensitivity to mechanical stress or electric fields.
• Understanding nanoscale piezoelectric behavior is crucial for advanced electronic devices.

Purpose of the Study:

• To investigate the source of enhanced piezoelectric response at the nanoscale.
• To explore the role of topological vortices in piezoelectricity.

Main Methods:

• Utilized in operando X-ray Bragg coherent diffraction imaging.
• Employed first-principles-based molecular dynamics simulations.

Main Results:

• Observed a 5-fold enhancement in piezoelectric response near topological vortex cores.
• Identified vortices as regions of coalescing low-symmetry ferroelectric phases and phase boundaries.
• Found largest nanoscale piezoelectric responses in regions of minimal spontaneous polarization at vortex cores.

Conclusions:

• Topological vortices are key to achieving high piezoelectric responses in pure BaTiO₃ at the nanoscale.
• Nanoscale piezoelectric materials can be designed by controlling vortex core parameters.
• Findings impact the development of next-generation piezoelectric materials for various applications.