Heterostructures consisting of SmNiO3 and NdNiO3 alternating layers with additional LaAlO3 spacer layers were grown and fully characterized by means of x-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy. A change in the orientation of the orthorhombic long-axis of the nickelate layers is observed when a single unit cell of LaAlO3 is inserted between SmNiO3 and NdNiO3, in agreement with density functional theory calculations. At the same time, the structure of the ultra-thin rhombohedral LaAlO3 layers is affected by their proximity to orthorhombic nickelate layers, with both scanning transmission electron microscopy studies and density functional theory calculations revealing a weak antipolar motion of the La-cation in the LaAlO3 layers that is not present in the bulk rhombohedral structure of this compound.

中文翻译：

---

镍基异质结构的结构研究

生长了由 SmNiO3 和 NdNiO3 交替层以及附加 LaAlO3 间隔层组成的异质结构，并通过 X 射线衍射、原子力显微镜和扫描透射电子显微镜对其进行了充分表征。当将 LaAlO3 的单个晶胞插入 SmNiO3 和 NdNiO3 之间时，观察到镍酸盐层的斜方长轴方向的变化，这与密度泛函理论计算一致。同时，超薄菱形LaAlO3层的结构受到其与正交镍酸盐层的接近的影响，扫描透射电子显微镜研究和密度泛函理论计算都揭示了LaAlO3中La阳离子的弱反极性运动该化合物的块体菱面体结构中不存在层。