  Active manipulation of mechanical waves at high frequencies opens
opportunities in heat management, radio-frequency (RF) signal processing, and
quantum technologies. Nanoelectromechanical systems (NEMS) are appropriate
platforms for developing these technologies, offering energy transducibility
between different physical domains, for example, converting optical or
electrical signals into mechanical vibrations and viceversa. Existing NEMS
platforms, however, are mostly linear, passive, and not dynamically
controllable. Here, we report the realization of active manipulation of
frequency band dispersion in one-dimensional (1D) nonlinear
nanoelectromechanical lattices (NEML) in the RF domain (10-30 MHz). Our NEML is
comprised of a periodic arrangement of mechanically coupled free-standing
nano-membranes, with circular clamped boundaries. This design forms a flexural
phononic crystals with a well-defined band gaps, 1.8 MHz wide. The application
a DC gate voltage creates voltage-dependent on-site potentials, which can
significantly shift the frequency bands of the device. Dynamic modulation of
the voltage triggers nonlinear effects, which induce the formation of phononic
band gaps in the acoustic branch. These devices could be used in tunable
filters, ultrasonic delay lines and transducers for implantable medical
devices.
