Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea.
Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
Adv Mater. 2023 Apr;35(15):e2208833. doi: 10.1002/adma.202208833. Epub 2023 Mar 6.
Interfaces between dissimilar correlated oxides can offer devices with versatile functionalities, and great efforts have been made to manipulate interfacial electronic phases. However, realizing such phases is often hampered by the inability to directly access the electronic structure information; most correlated interfacial phenomena appear within a few atomic layers from the interface. Here, atomic-scale epitaxy and photoemission spectroscopy are utilized to realize the interface control of correlated electronic phases in atomic-scale ruthenate-titanate heterostructures. While bulk SrRuO is a ferromagnetic metal, the heterointerfaces exclusively generate three distinct correlated phases in the single-atomic-layer limit. The theoretical analysis reveals that atomic-scale structural proximity effects yield Fermi liquid, Hund metal, and Mott insulator phases in the quantum-confined SrRuO . These results highlight the extensive interfacial tunability of electronic phases, hitherto hidden in the atomically thin correlated heterostructure. Moreover, this experimental platform suggests a way to control interfacial electronic phases of various correlated materials.
不同关联氧化物之间的界面可以为具有多种功能的器件提供条件，因此人们已经做出了巨大的努力来控制界面处的电子相。然而，由于无法直接获取电子结构信息，实现这些相通常会受到阻碍；大多数相关的界面现象出现在离界面几个原子层的范围内。在这里，原子级外延和光电子能谱被用来实现原子级钌钛酸盐异质结构中关联电子相的界面控制。虽然块状 SrRuO 是铁磁金属，但在单层极限下，异质界面只生成三种不同的关联相。理论分析表明，原子级结构近邻效应导致量子限制的 SrRuO 中出现费米液体、洪德金属和莫特绝缘体相。这些结果突出了电子相在原子薄的关联异质结构中广泛的界面可调性，而这在以前是隐藏的。此外，这个实验平台为控制各种关联材料的界面电子相提供了一种方法。
