Abstract Local coordination geometry is crucial in determining the physical properties of transition metal compounds. In this work, we report a detailed density functional theory study on the magnetic and electronic properties of layered Sr2NiO2Cl2, which possesses an unusual square planar coordination. Due to the crystal field and spin splitting, Ni 3d electrons fully occupy the dxz, dyz, and dxy orbitals, while partially occupy the d z 2 and d x 2 - y 2 states, leading to the high spin state of Ni2+ ions and strong antiferromagnetic in-plane nearest-neighbor exchange interaction J1. Thus, Sr2NiO2Cl2 is predicted to exhibit a G-type magnetic ground state, which all nearest-neighbor magnetic moments are antiparallel to each other in the NiO2 plane. A band gap is opened irrespective of the specific magnetic state since the unique square planar crystal field splitting. Finally, large orbital moments and giant easy-plane magnetocrystalline anisotropy energy are obtained, which is again related to the unique coordination environment.

中文翻译：

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具有方形平面配位的层状 Sr2NiO2Cl2 的磁和电子特性

摘要 局部配位几何对于确定过渡金属化合物的物理性质至关重要。在这项工作中，我们报告了对层状 Sr2NiO2Cl2 的磁性和电子性质的详细密度泛函理论研究，该层状 Sr2NiO2Cl2 具有不寻常的方形平面配位。由于晶体场和自旋分裂，Ni 3d 电子完全占据 dxz、dyz 和 dxy 轨道，同时部分占据 dz 2 和 dx 2 - y 2 态，导致 Ni2+ 离子的高自旋态和强反铁磁性-平面最近邻交换交互J1。因此，预计 Sr2NiO2Cl2 将呈现 G 型磁基态，即所有最近邻磁矩在 NiO2 平面中彼此反平行。由于独特的方形平面晶体场分裂，无论特定的磁态如何，带隙都会打开。最后，获得了大的轨道矩和巨大的易平面磁晶各向异性能量，这又与独特的配位环境有关。