Susarla Sandhya, García-Fernández Pablo, Ophus Colin, Das Sujit, Aguado-Puente Pablo, McCarter Margaret, Ercius Peter, Martin Lane W, Ramesh Ramamoorthy, Junquera Javier
National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
Nat Commun. 2021 Nov 1;12(1):6273. doi: 10.1038/s41467-021-26476-5.
Polar vortices in oxide superlattices exhibit complex polarization topologies. Using a combination of electron energy loss near-edge structure analysis, crystal field multiplet theory, and first-principles calculations, we probe the electronic structure within such polar vortices in [(PbTiO)/(SrTiO)] superlattices at the atomic scale. The peaks in Ti [Formula: see text]-edge spectra shift systematically depending on the position of the Ti cations within the vortices i.e., the direction and magnitude of the local dipole. First-principles computation of the local projected density of states on the Ti [Formula: see text] orbitals, together with the simulated crystal field multiplet spectra derived from first principles are in good agreement with the experiments.
氧化物超晶格中的极性涡旋呈现出复杂的极化拓扑结构。我们结合电子能量损失近边结构分析、晶体场多重态理论和第一性原理计算，在原子尺度上探究了[(PbTiO)/(SrTiO)]超晶格中此类极性涡旋内的电子结构。Ti [公式：见原文] 边光谱中的峰根据涡旋内Ti阳离子的位置（即局部偶极子的方向和大小）而系统地移动。Ti [公式：见原文] 轨道上局部投影态密度的第一性原理计算，以及从第一性原理导出的模拟晶体场多重态光谱与实验结果吻合良好。
