Vortex-mediated piezoelectric enhancement in bulk ferroelectrics
Topological polarization textures have transitioned from theoretical predictions to experimental observations over two decades, yet their stabilization has remained largely confined to low-dimensional architectures where geometric confinement balances depolarization, strain, and gradient energies. Extending these textures into bulk ferroelectrics and quantitatively linking them to macroscopic electromechanical properties constitutes a persistent challenge. Wu et al. address this by engineering vortex and antivortex domains in bulk rhombohedral 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-30PT) crystals. Phase-field simulations reveal that increasing vortex core density from 6 to 27 μm⁻² enhances the dielectric constant (ε33/ε0) and piezoelectric coefficient (d33) by approximately 3.5-fold and 3.4-fold, respectively, correlating with increased polarization curl. Experimentally, a mechanically assisted direct-current poling (MDCP) strategy elevates vortex core density from 0.01 to 21 μm⁻², boosting d33 from 1380 to 1820 pC·N⁻¹ and ε33/ε0 from 4,630 to 6,230. This mechanically driven approach enables controllable manipulation of topological domain architectures in bulk crystals without nanoscale confinement, offering a scalable route for functional optimization. The work establishes bulk ferroelectrics as a platform for topology-mediated electromechanical design, introducing an additional degree of freedom for enhancing piezoelectric performance in three-dimensional crystals.