  The possibility of realizing an electrostatically induced phononic crystal is
investigated numerically in an acoustic waveguide based on a graphene sheet
that is suspended over periodically arrayed electrodes. The application of dc
voltage to these electrodes exerts electrostatic force on the graphene and this
results in the periodic formation of stress in the waveguide structure in a
non-invasive way, unlike the cases with mass loading and air holes. This
non-invasive scheme enables a bandgap, namely a phononic crystal, to be created
in the waveguide that can be used to dynamically tune the acoustic transparency
in the medium. Our approach will allow the dispersion relation to be locally
modified, thus modulating the temporal response of traveling acoustic phonon
waves. This novel phonon architecture is promising in terms of realizing the
advanced control of phonon dynamics such as waveform and dissipation
engineering in the device.
