复杂氧化物界面新奇电子态的起源及调控

复杂氧化物界面因为呈现出体相不存在的新奇电子行为而在近年来受到了广泛的关注，也使其将来在氧化物电子学和自旋电子学器件中的应用成为可能。正是由于电荷、轨道和自旋自由度之间的复杂相互作用，在复杂氧化物界面处诱导出了如此丰富的电子行为。本项目拟基于第一性原理计算方法，以SrTiO3/LaAlO3异质结界面为出发点，通过改变界面化学计量比或化学组分，对薄膜施加外部电场或应力，调节界面极化薄膜的厚度或取向等多种手段，研究ABO3氧化物界面两侧晶体场、应力场、极化场、电荷转移、自旋交换和化学键结等相互作用之间的竞争和影响，控制其金属-绝缘体相变和磁性质的变化，拟揭示界面某些新奇电子态的起源，以及各种物理因素对界面物理特性的影响机制，并利用这些机制对界面新奇电子行为进行有效调控，预言新的量子现象和发现量子调控的新途径，以期能对复杂氧化物薄膜的进一步发展提供理论依据和指导。

Complex Oxide interfaces have attracted considerable attention in recent years due to the emerging novel behavior which does not exist in the corresponding bulk parent compounds. This opens possibilities for future applications in oxide-based electronics and spintronics devices. The rich behavior of complex oxide interfaces arises from the complex interactions between their charge, orbital, and spin degrees of freedom. This project is based on first-principle calculations and SrTiO3/LaAlO3 heterointerfaces. By altering the chemical stoichiometry or composition, applying the external electric field or strain, and modifying the thickness or orientation of polar films, we will study the competition and influence between the crystal field, strain, polarization, charge transfer, spin exchange, and chemical bonding. We purport to control the metal-insulator phase transition and magnetic properties, reveal the source of some novel interface states and the physical mechanism underlying the interface phenomena. In order to predict new quantum phenomena and discover new methods for quantum control, we will exploit these physical mechanism to tune the novel behavior at oxide interface. It is expected to provide theoretical foundation and guide for the further progress of complex oxide films.