A continuum energy approach of deformable piezoelectric and ferroelectric semiconductors

A nonlinear continuum theory of deformable piezoelectric and ferroelectric semiconductors is presented. Emphasis is placed on equations that cannot be obtained by the usual procedures in a consistent manner. The need for a new formulation is exhibited, then an energy approach that generalizes the Lagrangian procedure to nonintegrable systems is proposed. Nonintegrability is required so that the formulation accommodates irreversible processes and dissipative phenomena such as conduction and diffusion effects which play an important role in semiconductor devices. The author has recently showed the interest of such an approach in continuous media including interfacial properties. Here the attention is mainly focused on electromechanical coupling effects and a comparison is made between different works