Electronic Structure and Magnetic Coupling of Pure and Mg-Doped KCuF₃

Figure 1

Stick-and-ball representation of in the Pmmm space group (see text for details). For the sake of clarity, only half a cell is shown in the figure (0≤y≤0.5). The shifts of the position of F ions in the ab plane, in respect to the middle of the Cu-Cu internuclear axis as in cubic perovskite, are enlarged to highlight the deformation of octahedra. The partially filled orbitals responsible for orbital ordering are schematically represented in red.