论文标题
氧化物界面中固定时刻的起源的氧气空缺：四方Cuo/srtio $ _3 $的示例
Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$
论文作者
论文摘要
获得氧化物异质结构中新兴现象的准确理论描述是一个主要挑战。最近，通过X射线磁性圆形二分法测量在Cu $ l_ {2,3} $ - 四方CUO/SRTIO $ _3 $异源结构的X射线磁圆二色粒测量中发现了有趣的传感旋转和固定的轨道矩。使用第一原理计算，我们提出了一个方案，该方案是基于Tio $ _2 $接口层中氧空位的形成。我们显示了在界面CuO层中托有的顺磁性2D电子气体的出现。在Ti $ l_ {2,3} $ - 边缘上是看不见的，因为Ti原子的价保持不变。强大的结构扭曲破坏了界面处的本地和全局四倍旋转$ C_4 $对称性，导致靠近空位的Cu轨道矩的平面固定。我们的结果，尤其是轨道矩的固定，可能对其他系统有影响，尤其是具有相似金属氧键长和弱自旋轨道耦合的一氧化糖/二氧化物界面。
Obtaining an accurate theoretical description of the emergent phenomena in oxide heterostructures is a major challenge. Recently, intriguing paramagnetic spin and pinned orbital moments have been discovered by x-ray magnetic circular dichroïsm measurements at the Cu $L_{2,3}$-edge of a tetragonal CuO/SrTiO$_3$ heterostructure. Using first principles calculations, we propose a scenario that explains both types of moments, based on the formation of oxygen vacancies in the TiO$_2$ interface layer. We show the emergence of a paramagnetic 2D electron gas hosted in the interface CuO layer. It is invisible at the Ti $L_{2,3}$-edge since the valence of the Ti atoms remains unchanged. Strong structural distortions breaking both the local and global fourfold rotation $C_4$ symmetries at the interface lead to the in-plane pinning of the Cu orbital moment close to the vacancy. Our results, and in particular the pinning of the orbital moment, may have implications for other systems, especially monoxide/dioxide interfaces with similar metal-oxygen bond length and weak spin-orbit coupling.
