Fig. 1: Sketch of a ferroelectric/paraelectric superlattice periodically repeated along the stacking direction.
From: Giant voltage amplification from electrostatically induced incipient ferroelectric states
The thicknesses of the ferroelectric and dielectric layers are given by lf and ld, respectively; L = lf + ld is the thickness of the repeated unit. For an arbitrary external field \({{{{\mathcal{E}}}}}_{{{{\rm{ext}}}}}\), and in the absence of free carriers, all layers present the same vertical component of the displacement vector, so that Df = Dd. As illustrated in the figure, the displacement Di of layer i involves the layer polarization Pi, the field \({{{{\mathcal{E}}}}}_{{{{\rm{ind}}}},i}\) induced in the layer and the external field \({{{{\mathcal{E}}}}}_{{{{\rm{ext}}}}}\).
