Abstract：Due to the trend of miniaturization of electronic devices, the size of many piezoelectric thin film devices has reached the nanometer scale. The electric field and displacement field in piezoelectric thin film devices can be controlled by using temperature field. At present, the influence of the coupling between the first and second order deformation on the internal mechanical and electrical behavior of piezoelectric thin films has not been considered in the two-dimensional plate theory research on thermal stress. In this paper, the traditional elastic Mindlin plate model is extended to multiple physical fields, and the thermal stress and pyroelectric effect are considered, and the coupling relationship between thickness stretch deformation, in-plane extensional deformation and second-order shear deformation is considered. A piezoelectric film model with local temperature field is established. As an application, the effects of local temperature changes on the deformation and electric field of piezoelectric thin films were studied. The displacement field and electric potential field of piezoelectric films during the thickness stretch deformation are calculated by using Navier solution theory. Then a numerical study was carried out. The results showed that: Local heating (cooling) would lead to thickness stretch (shrinkage) deformation in the loading area, and with in-plane extensional (shrinkage) deformation and second-order shear deformation, the in-plane deformation of the film reached the maximum in the temperature loading area of the upper surface and the lower surface, and the two areas produced potential wells (potential barriers) and potential barriers (potential wells) respectively. This shows that the local temperature field can be used to control the deformation and electric field of the piezoelectric film. This study is an extension of the structural analysis theory of piezoelectric thin films with thermoelastic and pyroelectric effects, and provides a reference for the structural design and optimization of micro and nano scale devices.
2023, Vol. 44 
