Electronic band structures and magnetism of intermetallic Cu₂Sb-type manganese compounds MnAlGe and MnGaGe

Electronic band structures of intermetallic manganese compounds, MnAlGe and MnGaGe, having the Cu₂Sb-type crystal structure are calculated for both the non-magnetic and ferromagnetic states by a self-consistent augmented-plane-wave (APW) method. The gross features of the dispersion curve and the density of states of MnAlGe are similar to those of MnGaGe, Mn-3d states are hybridized with Al-3p or Ga-4p states and Ge-4p states. A strong two-dimensional character has been found in the Fermi surfaces obtained for the non-magnetic and ferromagnetic bands. The calculated magnetic moments in the ferromagnetic state are in good agreement with the observed results.