Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0299, USA.
Department of Mechanical and Materials Engineering & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588-0526, USA.
Adv Mater. 2017 Aug;29(31). doi: 10.1002/adma.201701385. Epub 2017 Jun 19.
Heteroepitaxial coupling at complex oxide interfaces presents a powerful tool for engineering the charge degree of freedom in strongly correlated materials, which can be utilized to achieve tailored functionalities that are inaccessible in the bulk form. Here, the charge-transfer effect between two strongly correlated oxides, Sm Nd NiO (SNNO) and La Sr MnO (LSMO), is exploited to realize a giant enhancement of the ferroelectric field effect in a prototype Mott field-effect transistor. By switching the polarization field of a ferroelectric Pb(Zr,Ti)O (PZT) gate, nonvolatile resistance modulation in the Mott transistors with single-layer SNNO and bilayer SNNO/LSMO channels is induced. For the same channel thickness, the bilayer channels exhibit up to two orders of magnitude higher resistance-switching ratio at 300 K, which is attributed to the intricate interplay between the charge screening at the PZT/SNNO interface and the charge transfer at the SNNO/LSMO interface. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy studies of SNNO/LSMO heterostructures reveal about 0.1 electron per 2D unit cell transferred between the interfacial Mn and Ni layers, which is corroborated by first-principles density functional theory calculations. The study points to an effective strategy to design functional complex oxide interfaces for developing high-performance nanoelectronic and spintronic applications.
异质外延耦合在复杂氧化物界面上为工程强关联材料中的电荷自由度提供了一种强大的工具，可以利用这种耦合来实现无法在体材料中实现的定制功能。在这里，我们利用两种强关联氧化物 SmNdNiO (SNNO) 和 LaSrMnO (LSMO) 之间的电荷转移效应，在原型莫特场效应晶体管中实现铁电场效应的巨大增强。通过切换铁电 Pb(Zr,Ti)O (PZT) 栅极的极化场，可以在具有单层 SNNO 和双层 SNNO/LSMO 沟道的莫特晶体管中诱导非易失性电阻调制。对于相同的沟道厚度，双层沟道在 300 K 下表现出高达两个数量级的更高电阻开关比，这归因于 PZT/SNNO 界面处的电荷屏蔽和 SNNO/LSMO 界面处的电荷转移之间的复杂相互作用。对 SNNO/LSMO 异质结构的 X 射线吸收光谱和 X 射线光电子能谱研究表明，界面 Mn 和 Ni 层之间每 2D 单位细胞转移约 0.1 个电子，这得到了第一性原理密度泛函理论计算的证实。这项研究为设计用于开发高性能纳米电子学和自旋电子学应用的功能性复合氧化物界面提供了一种有效的策略。
