Self-consistent relativistic APW calculation of the electronic structure of niobium with a non-muffin-tin potential

We report the results of a self-consistent relativistic augmented-plane-wave calculation of the electronic structure of Nb. This calculation was performed using potentials and charge densities of general shape; i. e. , the muffin-tin approximations of a spherical shape inside the muffin-tin spheres and constant in the interstitial region were both removed. The results are thus an accurate representation of the Hohenberg-Kohn-Sham formalism for Nb. We find that the results are generally better than those obtained using the full Slater (=1) overlapping-charge-density model. The effects of small changes in exchange parameter and lattice constant have also been calculated.