功能化氧化物异质结界面的双球差电镜原位实时表征

项目名称： 功能化氧化物异质结界面的双球差电镜原位实时表征

项目编号： No.11474147

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 王鹏

作者单位： 南京大学

项目金额： 90万元

中文摘要： 为突破当今微电子器件的尺寸极限，发展新一代多功能、低功耗器件技术，材料物理界亟需开展复杂功能材料及其界面结构的设计、构造与人工调控原理和方法的基础研究。相对于传统半导体，氧化物材料具有更加丰富的物理性质以及更广泛的表面界面结构组态、化学成分、电子学输运性能的可调控性， 因此完全有希望替代半导体界面成为新一代器件的主角。要全面深入理解其中的新奇物理现象，就必须精确掌握氧化物异质界面在几个埃范围内电子结构和原子结构的变化，这种从亚原子尺度上对结构进行实时有效的观测和表征是极具挑战性的。面临这样的机遇与挑战, 基于申请人在高分辨电镜技术和应用方面深厚的积累，本申请提出发展和利用亚原子分辨成像和相关谱学分析技术，研究功能氧化物异质界面的组分、原子结构、局域晶格应变、电子特性，以及在外场作用下的演化规律，深入探索界面上二维电子气形成的物理机理及其调控规律, 为发展新型信息存储器件提供科学依据。

中文关键词： 异质结；电子透射显微镜；二维电子气；过渡金属氧化物；高分辨

英文摘要： Interfaces between complex oxides and electronic systems with unusual electronic properties can be fabricated. Recently, motivated by the discovery of a high-mobility two dimensional electron gas (2DEG) with high carrier density at heterointerfaces combining two band insulators LaAlO3 and SrTiO3 (LAO/STO), numerous electronic properties at such interface have been deeply investigated, revealing superconducting and intriguing magneto-transport properties. These significant results show that 2DEG at complex oxide interfaces have an enormous potential with scientific and technological impacts on future oxide nanoelectronic devices. In order to develop high performance devices using oxide 2DEG, it is imperative to functionalize the physical properties of 2DEG in a controllable way. One possible way is to integrate 2DEG with additional functional layers such as multifunctional oxide/LAO/STO heterostructure. In this proposal, we use a functionalized oxide 2DEG system integrating epitaxial ferroelectric Pb（ZnxTi1-x）O3 (PZT) thin films on LAO/STO as a model system. We will first employ various advanced imaging techniques: HAADF, holography and EELS with sub-?ngstr?m resolution on an double aberration-corrected S/TEM to extract the maximum quantitative information on localized atomic and electronic structure and charge distribution at the interfaces. We will then combine TEM imaging and novel in-situ scanning probe techniques to study the kinetics and dynamics of the metal-insulating transition of 2DEG during ferroelectric switching of the PZT overlayer at millisecond temporal and sub-?ngstr?m spatial resolution in epitaxial heterostructure of PZT on LAO/STO under applied electric field. This proposed experimental study will reveal fundamental mechanism of the non-volatile control of 2DEG conductivity at the conducting polar/nonpolar oxide heterointerface for the development of novel memory nanoelectronics.

英文关键词： heterostructure;Transmission Electron Microscopy;Two-dimensional electron gas;Transitional Metal Oxide;High resolution