2026-04-19T18:33:07Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/1254882026-01-21T04:44:56Zcom_2072_1033col_2072_452950

00925njm 22002777a 4500 dc Abdollahi Hosnijeh, Amir author Vazquez Sancho, Fabian author Catalan, Gustau author 2018-11-15 The origin of “giant” flexoelectricity, orders of magnitude larger than theoretically predicted, yet frequently observed, is under intense scrutiny. There is mounting evidence correlating giant flexoelectriclike effects with parasitic piezoelectricity, but it is not clear how piezoelectricity (polarization generated by strain) manages to imitate flexoelectricity (polarization generated by strain gradient) in typical beam-bending experiments, since in a bent beam the net strain is zero. In addition piezoelectricity changes sign under space inversion but giant flexoelectricity is insensitive to space inversion, seemingly contradicting a piezoelectric origin. Here we show that, if a piezoelectric material has its piezoelectric coefficient asymmetrically distributed across the sample, it will generate a nonzero bending-induced polarization impossible to distinguish from true flexoelectricity even by inverting the sample. The effective flexoelectric coefficient caused by piezoelectricity is functionally identical to, and often larger than, intrinsic flexoelectricity: our calculations show that, for standard perovskite ferroelectrics, even a tiny gradient of piezoelectricity (1% variation of piezoelectric coefficient across 1 mm) is sufficient to yield a giant effective flexoelectric coefficient of 1 µC/m, three orders of magnitude larger than the intrinsic expectation value. Peer Reviewed Postprint (author's final draft) Àrees temàtiques de la UPC::Matemàtiques i estadística::Matemàtica aplicada a les ciències Strength of materials Resistència de materials Classificació AMS::74 Mechanics of deformable solids::74P Optimization Piezoelectric mimicry of flexoelectricity