Electronic Structure of RbMnFe(CN)₆: Ground State

Abstract

The electronic ground state of RbMnFe(CN)₆ is calculated by using all-electron full-potential linearized augmented-plane–wave (FLAPW) method in the local density approximation (LDA).With using the tetragonally distorted structure determined by the x-ray diffraction (XRD) measurement, we obtain the ferromagnetic ground state with the magnetization of 4 μ_B per chemical formula: the Mn moment is 3.17 μ_B, and the induced Fe moment is 0.25 μ_B. The tetragonal symmetry at the Mn site is crucial to obtain the insulating state; the Jahn–Teller splitting is as large as 0.7 eV between the up-spin Mn 3d(z²) and 3d(x²−y²). The energy bandgap (0.29 eV) exists between the up-spin Mn 3d(z²) band and the down-spin Mn 3d(xy) band. The result confirms that the electron configurations are the high-spin 3d⁴ for Mn and the low-spin 3d⁶ for Fe, which has been suggested by measurements of the magnetic susceptibility and the XRD.