Perovskite rare-earth nickelates are a prototypical class of quantum materials that exhibit rich phase-transition physics with promising applications in neuromorphic computing. Although there is existing experimental evidence demonstrating that strain may strongly influence the phase transitions of nickelate thin films, it would be extremely challenging to experimentally construct temperature-strain phase diagrams for different film orientations to guide applications. Here, we use the Ginzburg-Landau theory to formulate the thermodynamics of strained nickelates and calculate temperature-strain phase diagrams of epitaxial SmNiO3 and NdNiO3 thin films with various orientations, which are consistent with the limited existing experimental measurements. We predict that a shear strain can effectively tune the relative magnitude of the magnetic moments on the two nonequivalent Ni sublattices. Our theory provides an efficient theoretical framework for predicting the thermodynamics of strained nickelates, which will provide guidance for engineering their properties through strains.

中文翻译：

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应变工程的热力学 inRNiO3（R=Sm，Nd）


钙钛矿稀土镍酸盐是一类典型的量子材料，具有丰富的相变物理特性，在神经形态计算中具有广阔的应用前景。尽管现有的实验证据表明应变可能会强烈影响镍酸盐薄膜的相变，但通过实验构建不同薄膜取向的温度-应变相图以指导应用将极具挑战性。在这里，我们使用 Ginzburg-Landau 理论来制定应变镍酸盐的热力学，并计算具有不同取向的外延 SmNiO3 和 NdNiO3 薄膜的温度-应变相图，这与现有的有限实验测量一致。我们预测剪切应变可以有效地调节两个非等效 Ni 子晶格上磁矩的相对大小。我们的理论为预测应变镍酸盐的热力学提供了一个有效的理论框架，这将为通过应变设计其特性提供指导。