Correlated electrons give rise to both exotic electronic and magnetic properties in rare-earth nickelates. Here we present evidence of the interfacial coupling between two nickelate systems, ${\mathrm{EuNiO}}_3$ (ENO) and ${\mathrm{LaNiO}}_3$ (LNO), with different electronic and magnetic properties but with compatible structural registry giving rise to an electrostructural transition, unobserved in each constituent. Nominally, LNO remains in a paramagnetic-metallic $R\overline{3}c$ phase while orthorhombic ENO undergoes antiferromagnetic and insulating transitions. However, the ENO/LNO heterostructure displays a uniform rotational symmetry set by an entwined interface. This leads to an anomalous reduction of bond disproportionation in the ENO layer through the metal to insulator transition and concomitantly charge disproportionation opens the gap accompanied by antiferromagnetic ordering. Our results resolve a long-standing question in the physics of rare-earth nickelates, herein demonstrating that charge and bond disproportionation are competing mechanisms for the charge localization process in the rare-earth nickelate system.

中文翻译：

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稀土镍酸盐电子和晶格呼吸顺序竞争性质的直接证据。

相关的电子会在稀土镍酸盐中同时产生奇异的电子和磁性。在这里，我们提供了两个镍酸盐体系之间界面耦合的证据，${\mathrm{Ni}}_3$ （ENO）和 ${\mathrm{镧镍}}_3$（LNO），具有不同的电子和磁性，但具有相容的结构注册表，会引起电结构转变，在每个成分中均未观察到。名义上讲，LNO保留在顺磁性金属中$\mathrm{[R}\overline{3}C$正交的ENO经历反铁磁和绝缘转变。但是，ENO / LNO异质结构显示出由缠绕界面设置的均匀旋转对称性。这导致通过金属到绝缘体的过渡，使ENO层中的键歧化异常减少，并且伴随电荷电荷歧化，在反铁磁有序的情况下打开了间隙。我们的结果解决了稀土镍酸盐物理学上一个长期存在的问题，在此证明电荷和键歧化是稀土镍酸盐体系中电荷定位过程的竞争机制。