Crystal structure and electronic properties of CrAlGe

First-principles total energy calculations indicate that CrAlGe prefers a TiSi2-type structure to a Cu2 Sb-type one and that its magnetic ground state is ferromagnetic. These predictions are in agreement with experimental observation. As a result of consideration of the disorder between Al and Ge, it is found that the magnetic moment on Cr locally varies from site to site, but a magnetization per formula unit is almost constant. The analysis of electronic structure indicates a possibility that a ferromagnetic CrAl2−xGex (0 ≤x≤ 1) becomes half-metallic and that this nature is impervious to the disorder between Al and Ge.