A flexoelectric microelectromechanical system on silicon

Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment(1) and, conversely, to bend in response to an electric field(2). Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale(3). Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nano-electromechanical systems. Specifically, we have fabricated a silicon-compatible thin-film cantilever actuator with a single flexoelectrically active layer of strontium titanate with a figure of merit (curvature divided by electric field) of 3.33 MV-1, comparable to that of state-of-the-art piezoelectric bimorph cantilevers.