钙钛矿氧化物异质结中界面电子结构调制的研究

项目名称： 钙钛矿氧化物异质结中界面电子结构调制的研究

项目编号： No.11274060

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 董帅

作者单位： 东南大学

项目金额： 93万元

中文摘要： 钙钛矿结构过渡金属氧化物是典型的关联电子材料，其中自旋、轨道、电荷、晶格多重自由度相互耦合，展现出丰富的物理特性和广阔的应用前景。而氧化物薄膜和异质结则是关联电子材料走向实际器件应用的关键起点。在钙钛矿异质结中，两种材料界面处将发生复杂的晶格重组与电子重组。其中晶格重组指通过应力作用改变钙钛矿结构晶格畸变，从而改变材料的物性；而电子重组则是指通过界面处的电子转移（类似于半导体PN结）来调节界面处的电子结构（包括电荷分布、磁结构和耦合、轨道序）。本项目将研究多种钙钛矿结构异质结，重点关注晶格失配、电子转移等因素导致的界面重组效应以及如何人工控制异质结界面物理性质。主要研究内容包括:1)磁性氧化物超晶格(包括LaMnO3/SrMnO3,BiFeO3/LaSrMnO3等)的磁性转变和耦合、可电场控制的交换偏置；2）铁电/锰氧化物异质结的铁电场效应、铁电隧道结。本项目研究将以理论为主、实验为辅。

中文关键词： 钙钛矿氧化物；异质结；磁电耦合；界面/表面；超导

英文摘要： Transition metal oxides with the perovskite structure are typical correlated electron materials. In these systems, the couplings between multi-degree of freedom like charge, spin, orbital, and lattice, give rise to fasinating physical properties and promise board potential applications. To utilize correlated electron materials in devices, thin films and heterostructures of oxides are the key start points. In perovskite heterostructures, complex reconstructions of both the crystal structure and electronic structure will occur around the interfaces between two oxides. The reconstruction of crystal structure denotes the reshape of perovskite lattices driven by the strain/stress from the lattice mismatch, which will change materials' properties. Due to the electron transfer across the interfaces (like in the semiconductor PN junctions), the electron structure near interfaces, not only the charge distribution, but also the magnetic structures/couplings and orbital orders, will be rebuilt. In this project, several kinds of perovskite heterostructures will be investigated. The main goal is to reveal the underlying physical mechanisms during the interfacial reconstructions due to the lattice mismatch and electron transfer, and how to control them. The main subjects include: 1) Magnetic transitions and couplings in magne

英文关键词： Perovskite oxides；heterostructures；magnetoelectric coupling；interface/surface；superconductivity