Importance of second-order piezoelectric effects in zincblende semiconductors

We show that the piezoelectric effect that describes the emergence of an electric field in response to a crystal deformation in III-V semiconductors such as GaAs and InAs has strong contributions from second-order effects that have been neglected so far. We calculate the second-order piezoelectric tensors using density functional theory and obtain the piezoelectric field for [111]-oriented In$_x$Ga$_{1-x}$As quantum wells of realistic dimensions and concentration $x$. We find that the linear and the quadratic piezoelectric coefficients have the opposite effect on the field, and for large strains the quadratic terms even dominate. Thus, the piezoelectric field turns out to be a rare example of a physical quantity for which the first- and second-order contributions are of comparable magnitude.Comment: 4 pages, 3 figures, Submitted to Phys. Rev. Let

Theoretical Modelling on the Magnetization by Electric Field Through Product Property.

Multilayer composites of piezoelectric and magnetostrictive materials can be designed to exhibit the magnetoelectric (ME) effect. This ME effect can be realised as an electric polarisation induced by a magnetic field (called MEH effect) or a magnetization by an electric field (called MEE effect). Theoretical modelling of the MEE effect for 2-2 connectivity composites has been developed for three different boundary conditions for perfect coupling at the interface. The calculated MEE coefficients using material properties of piezoelectric lead zirconate titanate (PZT) and magnetostrictive Terfenol-D are a few orders of magnitude larger than those of single phase ME materials and the calculated values are compared with experimental results in the literature. Keywords: magnetoelectric, multiferroic, piezoelectric, magnetostrictive, piezomagnetic, laminated composites, modelling

Propagation and filtering of elastic and electromagnetic waves in piezoelectric composite structures

In this article we discuss the modelling of elastic and electromagnetic wave propagation through one- and two-dimensional structured piezoelectric solids. Dispersion and the effect of piezoelectricity on the group velocity and positions of stop bands are studied in detail. We will also analyze the reflection and transmission associated with the problem of scattering of an elastic wave by a heterogeneous piezoelectric stack. Special attention is given to the occurrence of transmission resonances in finite stacks and their dependence on a piezoelectric effect. A 2D doubly-periodic piezoelectric checkerboard structure is subsequently introduced, for which the dispersion surfaces for Bloch waves have been constructed and analysed, with the emphasis on the dynamic anisotropy and special features of standing waves within the piezoelectric structure.Comment: 24 pages, 18 figures, 3 tables. Preprint version of a research article, accepted for publication in "Mathematical Methods in the Applied Science (2016)

Rotator and extender ferroelectrics: Importance of the shear coefficient to the piezoelectric properties of domain-engineered crystals and ceramics

The importance of a high shear coefficient d15 (or d24) to the piezoelectric properties of domain-engineered and polycrystalline ferroelectrics is discussed. The extent of polarization rotation, as a mechanism of piezoelectric response, is directly correlated to the shear coefficient. The terms "rotator" and "extender" are introduced to distinguish the contrasting behaviors of crystals such as 4mm BaTiO3 and PbTiO3. In "rotator" ferroelectrics, where d15 is high relative to the longitudinal coefficient d33, polarization rotation is the dominant mechanism of piezoelectric response; the maximum longitudinal piezoelectric response is found away from the polar axis. In "extender" ferroelectrics, d15 is low and the collinear effect dominates; the maximum piezoelectric response is found along the polar axis. A variety of 3m, mm2 and 4mm ferroelectrics, with various crystal structures based on oxygen octahedra, are classified in this way. It is shown that the largest piezoelectric anisotropies d15/d33 are always found in 3m crystals; this is a result of the intrinsic electrostrictive anisotropy of the constituent oxygen octahedra. Finally, for a given symmetry, the piezoelectric anisotropy increases close to ferroelectric-ferroelectric phase transitions; this includes morphotropic phase boundaries and temperature induced polymorphic transitions.Comment: accepted in J. Appl. Phy

The Use of Piezoelectric Actuators in an Energy-Efficient Noise Reduction System

The piezoelectric effect allows for conversion between mechanical stress and electrical impulses. By utilizing this phenomenon, a novel method of sound attenuation was explored and tested in which a piezoelectric plate absorbs part of an incoming sound wave. Reversing the process allows a second plate to produce a phase-inverted wave using the absorbed energy, achieving further reduction through destructive interference