Comment on 'Theory of Giant Electromechanical Response from Ferroelectric Bilayers with Polydomain Structures due to Interlayer and Interdomain Coupling'

摘要

In a recent Letter [1], Mahjoub, Alpay, and Nagarajan presented a thermodynamic model of a ferroelectric bi-layer fabricated on a dissimilar thick substrate, which allows for the formation of ferroelastic domains in two layers. The authors employed the dense domain structure approach [2-4] introduced for individual films with domain periods much smaller than the film thickness. They tried to adapt to the case of a bilayer the theory of polydomain ferroelectric films [3,4], which takes into account the microscopic conditions fulfilled on ferroelastic domain walls and the macroscopic conditions imposed on the mean mechanical stresses and strains and the mean electric field in a polydomain film.