Kasinathan Deepa, Koepernik Klaus, Nitzsche Ulrike, Rosner Helge
Max-Planck-Institut für Chemische Physik fester Stoffe Dresden, D-01187 Dresden, Germany.
Phys Rev Lett. 2007 Dec 14;99(24):247210. doi: 10.1103/PhysRevLett.99.247210.
Cs2AgF4 was proposed to be an orbitally ordered ferromagnet based on recent neutron scattering data. Here, we report a detailed electronic structure study within the local spin density approximation also including strong Coulomb repulsion U. We investigate the influence of an orthorhombic distortion of the Ag environment and the importance of the on-site Coulomb repulsion. We find good quantitative agreement with both the experimentally observed exchange coupling and structural changes. Thus, our results strongly support that Cs2AgF4 is a strongly correlated charge-transfer insulator where the ferromagnetism is driven by orbital order.
基于最近的中子散射数据，Cs2AgF4被认为是一种轨道有序的铁磁体。在此，我们报告了在局域自旋密度近似下进行的详细电子结构研究，其中还包括强库仑排斥U。我们研究了Ag环境的正交畸变的影响以及在位库仑排斥的重要性。我们发现与实验观察到的交换耦合和结构变化都有很好的定量一致性。因此，我们的结果有力地支持了Cs2AgF4是一种强关联电荷转移绝缘体，其中铁磁性由轨道序驱动。
