Designing electromechanical metamaterial with full nonzero piezoelectric coefficients

Abstract

Designing topological and geometrical structures with extended unnatural parameters (negative, near-zero, ultrahigh, or tunable) and counterintuitive properties is a big challenge in the field of metamaterials, especially for relatively unexplored materials with multiphysics coupling effects. For natural piezoelectric ceramics, only five nonzero elements in the piezoelectric matrix exist, which has impeded the design and application of piezoelectric devices for decades. Here, we introduce a methodology, inspired by quasi-symmetry breaking, realizing artificial anisotropy by metamaterial design to excite all the nonzero elements in contrast to zero values in natural materials. By elaborately programming topological structures and geometrical dimensions of the unit elements, we demonstrate, theoretically and experimentally, that tunable nonzero or ultrahigh values of overall effective piezoelectric coefficients can be obtained. While this work focuses on generating piezoelectric parameters of ceramics, the design principle should be inspirational to create unnatural apparent properties of other multiphysics coupling metamaterials.

Tailoring Artificial Mode to Enable Cofired Integration of Shear‐type Piezoelectric Devices

“…When applied diagonally inverse-phase drive signals, every pair of subunits should work on d 31 extensional or contractional modes, respectively. [21,40,41] Their combined action will lead to an equivalent in-plane shear deformation, which is quasi-d 36 faceshear mode (see demonstration in Section S1 in the Supporting Information).…”

“…As the sole shear mode, applied electric field and initial poling direction of d 15 mode are in orthogonal orientations, and intermediate electrodes need polishing and re-preparing after polarization. [40,41] Whereas for cofired multilayer structures, the electrodes should be cosintered with piezolayers in one procedure and will not support reconstruction. [37,39] Single crystals of lower intrinsic symmetry may excite face shear (or d 36 ) mode, where the polarization is parallel to electric fields.…”

“…In our recent work, we revealed that apparently macroscopic broken symmetry of piezoceramics may be artificially established and further developed a methodology to design electromechanical metamaterials with overall nonzero effective coefficients beyond nature. [40] Inspired by the prediction that apparent face-shear mode of normal ceramics is supposed to be excited by arrayed functional subunits with programmed anisotropic polarization and external electric fields, we originally design and fabricate an artificial multilayer structure, and cofired integrated shear-type devices is expected to be realized for the first time.…”

Monolithic piezoceramic actuators with a twist

“…However, restricted by perpendicular applied electric fields and polarization of d 15 shear mode, neither piezoceramic twist plate actuators would support LTCC processes. Until recently, systematic methodologies on piezoelectric metamaterials and devices with ordered substructures have been proposed, which reveals that apparently macroscopic symmetry and synthetic deformation states of piezoceramics may be artificially rebuilt with the aid of patterned electrodes and arrayed piezo-units [32,33], and basic sheartype cofirable piezoceramic components are successfully invented [8]. These advances theoretically set the tone for further realizing twist actuation without the aforementioned puzzling weaknesses.…”

Giant Superelastic Piezoelectricity in Flexible Ferroelectric BaTiO3 Membranes

“…-theory view, the attractive electric force between the top and bottom sides of the folded membrane creates a torque on the fold: F = •2 . In equilibrium, this value equals to the bending torque that is required to fold a beam with bending stiffness to a radius of curvature : B = , while we assumed that the curvature satisfies: = 1/ .…”