Charge transfer or redistribution at oxide heterointerfaces is a critical phenomenon, often leading to remarkable properties such as two-dimensional electron gas and interfacial ferromagnetism. Despite studies on LaNiO 3 /LaFeO 3 superlattices and heterostructures, the direction and magnitude of the charge transfer remain debated, with some suggesting no charge transfer due to the high stability of Fe 3+ (3d 5 ). Here, we synthesized a series of epitaxial LaNiO 3 /LaFeO 3 superlattices and demonstrated partial (up to ~0.5 e − /interface unit cell) charge transfer from Fe to Ni near the interface, supported by density functional theory simulations and spectroscopic evidence of changes in Ni and Fe oxidation states. The electron transfer from LaFeO 3 to LaNiO 3 and the subsequent rearrangement of the Fe 3d band create an unexpected metallic ground state within the LaFeO 3 layer, strongly influencing the in-plane transport properties across the superlattice. Moreover, we establish a direct correlation between interfacial charge transfer and in-plane electrical transport properties, providing insights for designing functional oxide heterostructures with emerging properties.

中文翻译：

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界面电荷转移及其对LaNiO 3 /LaFeO 3超晶格输运性能的影响


氧化物异质界面的电荷转移或重新分布是一种关键现象，通常会导致显着的特性，例如二维电子气体和界面铁磁性。尽管对 LaNiO 3 /LaFeO 3 超晶格和异质结构进行了研究，但电荷转移的方向和大小仍然存在争议，一些人认为由于 Fe 3+ （3d 5） 的高稳定性，没有电荷转移。在这里，我们合成了一系列外延 LaNiO 3 /LaFeO 3 超晶格，并证明了在界面附近从 Fe 到 Ni 的部分（高达 ~0.5 e − /界面晶胞）电荷转移，这得到了密度泛函理论模拟和 Ni 和 Fe 氧化态变化的光谱证据的支持。从 LaFeO 3 到 LaNiO 3 的电子转移以及随后的 Fe 3d 波段重排在 LaFeO 3 层内产生了意想不到的金属基态，强烈影响了超晶格上的面内传输特性。此外，我们建立了界面电荷转移和面内电传输特性之间的直接相关性，为设计具有新兴特性的功能性氧化物异质结构提供了见解。