Abstract
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.
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Acknowledgements
The work at ICN2 was funded by an ERC Starting Grant from the EU (Project No. 308023), a National Plan grant from Spain (FIS2013-48668-C2-1-P) and the Severo Ochoa Excellence programme. The work at Cornell University was supported by the National Science Foundation (Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems) under grant number EEC-1160504. The authors thank E. Cuche, J. Parent, E. Solanas and Y. Emery for discussions.
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G.C. and U.B. conceived and designed the experiments. N.B. designed and made the cantilevers under the supervision of G.R. U.B. performed and analysed the inverse flexoelectric characterizations under the supervision of G.C. A.A. performed the self-consistent continuum modelling and simulations. Z.W. performed the molecular beam epitaxy growth of the template layer under the supervision of D.S. U.B. and G.C. wrote the paper with the help of all the other authors. All authors discussed the results, commented on the manuscript and gave their approval to the final version of the manuscript.
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Bhaskar, U., Banerjee, N., Abdollahi, A. et al. A flexoelectric microelectromechanical system on silicon. Nature Nanotech 11, 263–266 (2016). https://doi.org/10.1038/nnano.2015.260
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DOI: https://doi.org/10.1038/nnano.2015.260
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