Title: A compositional ordering-driven morphotropic phase boundary in ferroelectric solid solutions Show Chinese title

Title: 铁电固溶体中的组成有序驱动型突变相边界

Abstract: Ferroelectric solid solutions usually exhibit giant dielectric response and high piezoelectricity in the vicinity of the morphotropic phase boundary (MPB), where the structural phase transitions between the rhombohedral and the tetragonal phases as a result of the composition or strain variation. Here, we propose a compositional ordering-driven MPB in the specified compositional solid solutions. By preforming machine-learning potential based molecular dynamics simulations on lead zirconate titanate, we find a phase transition from the rhombohedral to tetragonal phase with the decrease of compositional ordering, leading to the MPB on temperature-ordering phase diagram. The compositional ordering-driven MPB can enhances the piezoelectricity with a magnitude comparable to that at the composition-driven MPB. Finally, we demonstrate that the mechanism of high piezoelectricity is polarization rotation driven by external field. This work provides an additional degree of freedom, compositional ordering, to design the high-performance piezoelectric materials. Show Chinese abstract

Abstract: 铁电固溶体通常在反铁电相界（MPB）附近表现出巨大的介电响应和高压电性，这是由于成分或应变变化导致的菱形相和四方相之间的结构相变。 在这里，我们提出了在特定成分固溶体中的成分有序驱动的MPB。 通过对钛酸铅锆进行基于机器学习势的分子动力学模拟，我们发现随着成分有序性的降低，会发生从菱形相到四方相的相变，从而在温度-有序相图上形成MPB。 成分有序驱动的MPB可以增强压电性，其幅度与成分驱动的MPB相当。 最后，我们证明了高压电性的机制是由外场驱动的极化旋转。 这项工作提供了一个额外的自由度，即成分有序，用于设计高性能的压电材料。