The electronic structure of MnBi

Abstract

The first self-consistent spin-polarised band-structure calculation of the ferromagnetic compound MnBi in its low-temperature phase has been performed. The spin-orbit interaction was treated as a perturbation using scalar-relativistic wavefunctions. On the Mn atoms an effective 3d5.5 configuration is found, with a magnetic moment of 3.6 mu B. A part of the d electrons is rather delocalised and strongly hybridised with Bi 6p states. This leads to a low density of states at the Fermi level in agreement with experiment. The calculated band structure is very similar to that of MnSb. The physical properties of both compounds are compared, and the dependence of the band structure on the direction of the spin magnetic moment is discussed in relation to the magnetic anisotropy and the magneto-optical polar Kerr effect.