Due to the strain gradient near each surface of a BaTiO3 nanocube in their ordered assembly, electric polarization appears due to flexoelectric effect. The magnitude of the flexoelectric polarization could be one order of magnitude larger than that of ferroelectric spontaneous polarization of BaTiO3. Thus, dielectric response of an assembly could be dominated by that of the flexoelectric polarization if there is no ferroelectric domain-wall motion. Numerical simulations of the dielectric response of a BaTiO3 nanocube in an ordered assembly are performed from kHz to MHz range based on a dynamic model of flexoelectric polarization assuming anharmonic potential. The calculated temperature dependence of the dielectric constant is consistent with the experimental data of high dielectric constant with nearly-flat temperature dependence. It is suggested that high dielectric constant with nearly-flat temperature dependence is not originated in ferroelectric nature of BaTiO3 nanocubes but originated in flexoelectric polarization in nanocubes which is also seen in non-ferroelectric materials.

中文翻译：

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BaTiO3纳米立方体有序组装中从kHz到MHz范围内的挠曲电极化的动态介电响应模型

由于有序组装中 BaTiO3 纳米立方体的每个表面附近的应变梯度，由于挠曲电效应而出现电极化。挠曲电极化的幅度可能比 BaTiO3 的铁电自发极化大一个数量级。因此，如果没有铁电畴壁运动，组件的介电响应可能由挠曲电极化的介电响应支配。基于假设非谐波电位的挠曲电极化动态模型，对有序组件中 BaTiO3 纳米立方体的介电响应进行数值模拟，范围从 kHz 到 MHz。计算出的介电常数的温度依赖性与具有接近平坦温度依赖性的高介电常数的实验数据一致。