基于SrTMO3（TM = Ti/Ru/Ir）的异质结磁构型的第一原理设计与调控

过渡金属氧化物因具有自旋、电荷、轨道、晶格等自由度而呈现出丰富的磁性质，4d/5d电子的自旋轨道耦合效应将磁矩方向与晶体结构紧密联系在一起，在异质结中则有望通过界面工程实现特定的磁构型。过渡金属氧化物异质结的磁构型决定于若干电子自由度的竞争，密度泛函理论通常因为不能可靠描述d电子关联性质、从而难以准确反映这些耦合作用。SCAN交换关联泛函是密度泛函理论的一个重要进展，申请人发现SCAN能够比较可靠地模拟高温超导铜氧化物等关联体系的若干性质，而且更适用于中度关联4d/5d氧化物体系。基于上述研究，本项目将设计钙钛矿结构SrTMO3（TM=Ti/Ru/Ir）异质结，利用界面工程调控异质结的磁构型，以期实现铁磁性、垂直磁化等具有应用前景或新奇物性的体系。本项目还将研究异质结磁构型的电子结构机理，模拟与研究磁构型对外加电场的响应行为与微观机制，为开发全电场控制的自旋电子器件准备前期基础理论。

Transition-metal oxides (TMO) harbor diversified magnetic properties because of the subtle interplay of spin, charge, orbital, and lattice degrees of freedom of TM-d electrons. In 4d/5d-TMOs, orientations of the magnetic moments strongly couple with the lattice because of the strong spin-orbit interaction of 4d/5d electrons. Heterostructures is an effective way to tune magnetic configurations via various interface engineering techniques. For theoretical investigation of TMO-heterostructures, density functional theory (DFT) is a powerful tool, but it also meets strong limitations because of the significant self-interaction error in the conventional local/semilocal exchange-correlation functionals, which restricts the predicting power of DFT. The recently developed SCAN metaGGA makes a substantial advancement in predicting the electronic properties of cuprates with strongly-correlated 3d states, and is also found to be very accurate for the moderately-correlated 4d/5d electrons. Based on my previous investigations, I propose to study the magnetic properties of heterostructures composed of SrTMO3 (TM = Ti/Ru/Ir) perovskites. I will first design and optimize several heterostructures with particular magnetism either for device applications or with novel properties. Second, I will study the electronic mechanisms in determining the specific magnetic configurations, and will also simulate their behaviors within an electric field to look into the possibility for future all-electric spintronic devices.