With the recent discovery of superelastic behaviors of ferroelectric (piezoelectric) ceramics, understanding their non-linear mechanical and electromechanical responses under high stress and electric field conditions is crucial for engineering and designing advanced piezoelectric devices, such as ultrasmall actuator systems. In this study, we carry out first-principles finite electric field calculations to clarify the mechanical and electromechanical properties under the electric field for typical ferroelectric ceramics of PbTiO. Superelastic-like non-linear deformation behavior is enhanced or suppressed depending on the electric field direction, suggesting the possible design of superelasticity. We clarified that positive and negative electric fields to spontaneous polarization promote and inhibit deformation due to strain loading, thereby providing tunable superelasticity. We also investigate the mechanical loading and electric field dependence of the piezoelectric coefficient of PbTiO. The tunable piezoelectric response can be provided with a coupling of mechanical loading and electric field. Finally, we present higher-order piezoelectric constitutive equations applicable for superelastic-like non-linear deformations under an electric field. The present results will open promising paradigms for functional piezoelectric devices, and the proposed piezoelectric constitutive equations broaden the design scope through finite element method analysis.

中文翻译：

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机电耦合场下铁电 PbTiO[公式省略]陶瓷的超弹性机电行为：基于第一原理的高阶压电本构方程


随着最近发现铁电（压电）陶瓷的超弹性行为，了解它们在高应力和电场条件下的非线性机械和机电响应对于工程和设计先进压电器件（例如超小型致动器系统）至关重要。在本研究中，我们进行了第一性原理有限电场计算，以阐明典型的 PbTiO 铁电陶瓷在电场下的机械和机电性能。类超弹性非线性变形行为根据电场方向而增强或抑制，这表明了超弹性的可能设计。我们阐明了自发极化的正电场和负电场会促进和抑制应变载荷引起的变形，从而提供可调节的超弹性。我们还研究了 PbTiO 压电系数的机械载荷和电场依赖性。可通过机械负载和电场的耦合来提供可调谐压电响应。最后，我们提出了适用于电场下类超弹性非线性变形的高阶压电本构方程。目前的结果将为功能性压电器件开辟有前景的范例，并且所提出的压电本构方程通过有限元方法分析拓宽了设计范围。