锰氧化物异质结界面的电荷转移、轨道重构和磁性能及其调控研究

Manganite heterosstructures with novel interface ferromagnetism have attracted much attention for a wide range of applications in the spin-polarization detector, quantum computer, magnetic sensor, ferromagnetic random access memory and other electronic components. The interface magnetism can be modulated by charge transfer and orbital reconstruction in the interface of the manganite heterostructure. Recently, how to effectively control the interface ferromagnetism by tuning the charge transfer and orbital reconstruction keeps to be a critical issue. Although the charge transfer effects and orbital reconstruction at the interfaces have been recently studied to describe the interface coupling in the heterostructures, the origin of the charge transfer across the interface still remains a controversial issue. In addition, there is still a lack of adequate experimental study to modulated the interface ferromagnetism by tuning the charge transfer and orbital reconstruction at the interface in these systems. In this work, the valence band offset has been investigated in detail to understand and explain the origin of the charge transfer in the manganite heterostructures. At the same time, the physcial properties will be modulated by tuning the charge transfer and orbital reconstruction at the interface through doping and strain. It is theoretically instructive to carry out this project for manipulation the physical properties of the manganite heterostructure and other oxide functional films.

锰氧化物异质结界面存在独特的界面磁耦合性能，在自旋极化探测器、量子计算机、磁场感应器件和磁性存储等技术领域中具有重要的应用。锰氧化物异质结可以通过界面电荷转移和轨道重构实现新的磁有序相，因而表现出丰富的磁耦合性能。实现锰氧化物异质结实用化的基础和核心问题是如何通过界面电荷转移和轨道重构有效的调控界面磁耦合性能。尽管实验上可以利用锰氧化物异质界面电荷转移和轨道重构来讨论界面磁耦合，但是对于其电荷转移微观机制却一直没能进行深入讨论，锰氧化物异质结界面电荷转移和轨道重构的调控机制尚不清楚。本项目通过改变锰氧化物异质结界面的价带偏移值来调控界面电荷转移，揭示锰氧化物异质结界面电荷转移的机制问题；同时，通过掺杂和应力场来压调控界面电荷转移和轨道重构，实现其物理性能的调控。本项目的开展将为锰氧化物异质结以及其它功能氧化物异质结的物理性能的调控提供理论指导。

锰氧化物异质结界面存在独特的界面磁耦合性能，在自旋极化探测器、量子计算机、磁场感应器件和磁性存储等技术领域中具有重要的应用。锰氧化物异质结可以通过界面电荷转移和结构重构实现新的磁有序相，因而表现出丰富的磁耦合性能。实现锰氧化物异质结实用化的基础和核心问题是如何通过界面电荷转移和轨道有效的调控界面磁耦合性能。.本项目研究的主要内容有两个：其一，通过改变异质结界面价带偏移值和界面结构来调控界面电荷转移，揭示锰氧化物异质结界面电荷转移的机制问题，阐明锰氧化物异质结界面价带电荷转移和轨道重构对物理性能的影响及其作用机制；其二，通过改变调控界面类型来调控界面电荷转移，揭示界面结构重构对界面电荷转移和轨道重构的作用机制，阐明界面结构重构对界面电子结构的影响和对界面物理性能的作用机制。 本项目的开展将为锰氧化物异质结以及其它功能氧化物异质结的物理性能的调控提供理论指导。.实际研究工作按计划进行，本项目所获得的两个重要结果为：1）通过制备LaSrMnO/BiFeO3异质结，控制锰氧化物界面阳离子价态，改变界面价带偏移值，实现界面电荷转移，研究了界面效应对磁学性能的作用机制； 2）通过制备调控界面电荷转移，利用界面轨道重构，实现了界面磁耦合的调控。