Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA.
Nat Mater. 2012 Oct;11(10):855-9. doi: 10.1038/nmat3405. Epub 2012 Aug 19.
Controlling the electronic properties of interfaces has enormous scientific and technological implications and has been recently extended from semiconductors to complex oxides that host emergent ground states not present in the parent materials. These oxide interfaces present a fundamentally new opportunity where, instead of conventional bandgap engineering, the electronic and magnetic properties can be optimized by engineering quantum many-body interactions. We use an integrated oxide molecular-beam epitaxy and angle-resolved photoemission spectroscopy system to synthesize and investigate the electronic structure of superlattices of the Mott insulator LaMnO(3) and the band insulator SrMnO(3). By digitally varying the separation between interfaces in (LaMnO(3))(2n)/(SrMnO(3))(n) superlattices with atomic-layer precision, we demonstrate that quantum many-body interactions are enhanced, driving the electronic states from a ferromagnetic polaronic metal to a pseudogapped insulating ground state. This work demonstrates how many-body interactions can be engineered at correlated oxide interfaces, an important prerequisite to exploiting such effects in novel electronics.
控制界面的电子特性具有巨大的科学和技术意义，最近已从半导体扩展到复杂氧化物，这些氧化物中存在母体材料中不存在的新兴基态。这些氧化物界面提供了一个全新的机会，在这里，可以通过工程量子多体相互作用来优化电子和磁性性质，而不是传统的能带工程。我们使用集成的氧化物分子束外延和角分辨光发射光谱系统来合成和研究莫特绝缘体 LaMnO(3)和带绝缘体 SrMnO(3)超晶格的电子结构。通过以原子层精度数字地改变（LaMnO(3))(2n)/(SrMnO(3))(n)超晶格中界面之间的间隔，我们证明了量子多体相互作用得到了增强，将电子态从铁磁极化子金属驱动到赝隙绝缘基态。这项工作展示了如何在相关氧化物界面上设计多体相互作用，这是利用新型电子学中这种效应的重要前提。
