Induced giant piezoelectricity in centrosymmetric oxides

Abstract

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle for finding piezoelectric materials. We circumvented this limitation by breaking the crystallographic symmetry and inducing large and sustainable piezoelectric effects in centrosymmetric materials by the electric field–induced rearrangement of oxygen vacancies. Our results show the generation of extraordinarily large piezoelectric responses [with piezoelectric strain coefficients ( d 33 ) of ~200,000 picometers per volt at millihertz frequencies] in cubic fluorite gadolinium-doped CeO 2− x films, which are two orders of magnitude larger than the responses observed in the presently best-known lead-based piezoelectric relaxor–ferroelectric oxide at kilohertz frequencies. These findings provide opportunities to design piezoelectric materials from environmentally friendly centrosymmetric ones.

“Forbidden” Polarisation and Extraordinary Piezoelectric Effect in Organometallic Lead Halide Perovskites

“…This situation is analogous to that in oxides with fluorite structure where large induced piezoelectric response is also related to a high mobility of oxygen ions via oxygen vacancy migration. [ 41 ] In contrast, in ferroelectric oxide perovskites the origin of the intrinsic piezoelectric effect is in electrostriction biased by the spontaneous polarization, $${P_S}$$, and intrinsic permittivity, [ 42 ] where long range motion of ionic defects does not contribute substantially to the polarization and permittivity. Note that we compare MAPbX 3 with perovskite oxides only to demonstrate how various contributions to the polarization may have vastly different effect on the electro‐mechanical coupling in materials with the same crystal structure.…”

“…The effects of long‐range ionic displacement on electro‐mechanical properties revealed in our work should not be limited to organometallic perovskites but are expected to be present in other materials with substantial ionic migration, such as family of fluorites. [ 41 ] These effects can be classified under the general category of ferroionic‐like [ 65 ] phenomena, even if ferroelectricity is absent.…”

Mott Insulator Ca2RuO4 under External Electric Field

“…We also calculate the piezoelectric tensor, which is zero for centrosymmetric crystal structures [ 49 ]. Therefore, in order to obtain a piezoelectric tensor different from zero in systems such as Ca RuO we have to break the inversion symmetry [ 50 , 51 , 52 ]. We have shifted the Ru atoms along the z -axis to break the inversion symmetry, as shown in Figure 1 a, and we have calculated the components of the tensor.…”

Self‐Assembled LaFeO3/ZnFe2O4/La2O3 Ultracompact Hybrids with Enhanced Piezo‐Phototronic Effect for Oxygen Activation in Ambient Conditions

“…Further structural analysis indicates that the crystal structures of La 2 O 3 and spinel ZnFe 2 O 4 in the self-assembled hybrids are non-centrosymmetric, which is the basic prerequisite to be piezoelectric. [14,30,31] A schematic illustration of the crystal structures of both phases is given in Figure S1 (Supporting Information). Due to the structural anisotropy nature, the atomic displacement within the unit cell (when subjected to external mechanical vibration) would result in the mismatch of the cation and anion centers, consequently generating a dipole moment, the behavior known as polarization.…”