ELECTRONIC-STRUCTURE OF QUASI-2-DIMENSIONAL BANIS2

The band properties of layered BaNiS2, an end member of the BaCo1-xNix S2-y alloy series which exhibits an insulator-to-metal transition with decreasing temperature, have been calculated via the linear augmented -plane-wave method. The results feature a broad (-8.5 eV) Ni(3d)-S(3p) valence manifold, with partially-filled d(x-y)(22)-type sigma() band s near E(F) that are overlapped by d(3z-r)(22) and d(xz)-d(yz) subband s. Although BaNiS 2 shares structural and electronic characteristics w ith cuprate high-T-c superconductors, its calculated band properties n ear E(F) are decidedly less two dimensional than those of typical cupr ates like La2CuO4.