Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment1 and, conversely, to bend in response to an electric field2. Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale3. Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nanoelectromechanical 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.
Bhaskar, U. K., Banerjee, N., Abdollahi, A., Wang, Z., Schlom, D. G., Rijnders, A. J. H. M., & Catalan, G. (2016). A flexoelectric microelectromechanical system on silicon. Nature nanotechnology, 11, 263-266. https://doi.org/10.1038/NNANO.2015.260