Paper detail

Quasistatic stopband in the spectrum of one-dimensional piezoelectric phononic crystal

Propagation of a longitudinal wave through the periodic structure composed of alternating elastic and piezoelectric layers is considered. The faces of each piezoelectric layer are electroded and connected via a circuit with the capacity $C$. It is shown that if $C<0$ then the Floquet-Bloch spectrum $ ω(K)$ in a certain range of negative $C$ may possess a quasistatic absolute stopband starting at $ω=0$. Other unusual features of the spectrum occurring at certain fixed values of $C<0$ are the infinite group velocity of the first branch at the origin point $ω=0$, $K=0$ and the flat bands $ω={\rm const}$.