Many technologically critical materials are metastable under ambient conditions, yet the understanding of how to rationally design and guide the synthesis of these materials is limited. This work presents an integrated approach that targets a metastable lead‐free piezoelectric polymorph of SrHfO₃. First‐principles calculations predict that the previous experimentally unrealized, metastable P4mm phase of SrHfO₃ should exhibit a direct piezoelectric response (d₃₃) of 36.9 pC N⁻¹ (compared to d₃₃ = 0 for the ground state). Combining computationally optimized substrate selection and synthesis conditions lead to the epitaxial stabilization of the polar P4mm phase of SrHfO₃ on SrTiO₃. The films are structurally consistent with the theory predictions. A ferroelectric‐induced large signal effective converse piezoelectric response of 5.2 pm V⁻¹ for a 35 nm film is observed, indicating the ability to predict and target multifunctionality. This illustrates a coupled theory‐experimental approach to the discovery and realization of new multifunctional polymorphs.

中文翻译：

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亚稳态无铅压电多晶型物的理论指导合成

许多技术关键的材料在环境条件下都是亚稳态的，但是对如何合理设计和指导这些材料的合成的理解是有限的。这项工作提出了一种针对SrHfO ₃的亚稳态无铅压电多晶型物的综合方法。第一性原理计算预测，先前的SrHfO ₃实验未实现的亚稳态P4 mm相应表现出36.9 pC N ^-1的直接压电响应（d ₃₃）（相比之下，基态d ₃₃ = 0）。结合计算优化的衬底选择和合成条件，可实现极性P4 mm的外延稳定SrTiO ₃上SrHfO _3的相。这些膜在结构上与理论预测一致。对于35 nm的薄膜，观察到铁电感应的大信号有效逆压电响应为5.2 pm V ^-1，表明了预测和靶向多功能的能力。这说明了一种用于新多功能多晶型物发现和实现的理论-实验耦合方法。