Energy bands, electronic properties, and magnetic ordering of CrB2

The energy bands of the compound Cr${\mathrm{B}}_2$ have been calculated by using the Korringa-Kohn-Rostoker method in the muffin-tin-potential approximation. The bands near the Fermi level have mostly Cr $d$ character, and one of the bands gives rise to a very flat piece of Fermi surface perpendicular to the hexagonal axis. We propose that this piece of Fermi surface stabilizes a spin-density-wave state which manifests itself as antiferromagnetic ordering of the compound below 85 K. We also interpret the excess specific heat and electronic-spin susceptibility as due to exchange enhancement.