Mathematical analysis of an acoustically actuated nanospherical antenna with terahertz frequency range applications in the framework of generalized spectral magneto-electro-elastodynamic interface theory

This paper undertakes a comprehensive exploration of multiphysics phenomena involving electromagnetic (EM) radiation emitted by a nanospherical piezoelectric scatterer embedded in a polymer matrix, subjected to P waves within the THz frequency spectrum. A nanosized piezoelectric scatterer as a potential antenna possesses a significant surface-to-volume ratio. Consequently, it becomes imperative to meticulously account for the nanoscopic polarization vector, residual polarization vector, stress field, and residual stress field at its interface with the surrounding matrix. The conventional electrodynamics theory falls short in addressing the problem of interest, primarily due to its oversight of the magneto-electro-elastic interface. One of the aims of the current work is to extend the previously devised mathematical framework of surface/interface elasticity theory for purely elastic medium at the nanoscale, to magneto-electro-elastic (MEE) medium. By harnessing the versatility of spherical harmonics, we have simultaneously solved the fully coupled elastodynamics and Maxwell's equations within the mathematical framework of spectral MEE surface/interface theory. In this study, we scrutinize specific nuances related to the introduced surface/interface characteristic lengths. This exploration enables us to examine the influence of size on EM radiated power, the fundamental resonance frequency, and the distribution of the magnetic field. The insights gained from our findings hold promise for the design of acoustically actuated nanospherical antennas, nanosensors, and nanoresonators utilizing piezoelectric nanospheres.