Flexoelectricity describes the generation of electric polarization in response to inhomogeneous strain, i.e., strain gradient, in all dielectrics. Importantly, strain gradients are inversely scaled to the material dimension so that more prominent and exotic phenomena can be envisioned at the nanoscale, based on flexoelectricity. In particular, in complex oxides, such a large lattice inhomogeneity can also host a rich spectrum of properties and functionalities, via a subtle interplay with charge, spin, and orbital. Here, motivated by advances in nanoscale thin-film and membrane syntheses of complex oxides, we present the frontiers and challenges of flexoelectricity. Together with the advanced synthesis techniques, state-of-the-art experimental nano-techniques will continue to reveal hitherto hidden functionalities through flexoelectricity. Meanwhile, further breakthroughs in the research of flexoelectricity will require consistency between theory and experiment and will rely on the versatile exploitation of large strain gradients in nanoscale complex oxides.

中文翻译：

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复合氧化物薄膜和膜中的柔电性

柔性电描述了在所有电介质中响应非均匀应变（即应变梯度）而产生的电极化。重要的是，应变梯度与材料尺寸成反比，因此基于挠曲电性，可以在纳米尺度上设想更突出和奇异的现象。特别是，在复杂的氧化物中，通过与电荷、自旋和轨道的微妙相互作用，如此大的晶格不均匀性也可以拥有丰富的性质和功能。在这里，受复合氧化物纳米级薄膜和膜合成进展的推动，我们介绍了柔性电的前沿和挑战。连同先进的合成技术，最先进的实验纳米技术将继续通过柔性电揭示迄今为止隐藏的功能。