The Structural, Electronic, and Magnetic Properties of Cobalt Disulfide Doped with Oxygen, Selenium, or Tellurium.

The structural, electronic, and magnetic properties of cobalt disulfide (CoS₂) doped with oxygen (O), selenium (Se), or tellurium (Te) were investigated based on the spin-polarized first-principles calculations. Both the lattice constant and volume for CoO_0.25S_1.75 were smaller while those for CoSe_0.25S_1.75 and CoTe_0.25S_1.75 were larger than the corresponding values for CoS₂. Both CoS₂ and CoO_0.25S_1.75 were quasi-half-metallic, and both CoSe_0.25S_1.75 and CoTe_0.25S_1.75 were quasi-metallic. For CoS₂, CoSe_0.25S_1.75, and CoTe_0.25S_1.75, the valence band maximums (VBMs) were contributed by Co-3d(t_2g) states near the X-point, and the conduction band minimums (CBMs) were contributed by S-3p states at the Γ-point. For CoO_0.25S_1.75, the VBM was contributed by Co-3d(t_2g) states at the M-point, and the CBM was contributed by Co-3d(e_g) states near the R-point. Both O-S and Te-S dimers were strongly polarized, and the Se-S dimer was slightly polarized. CoS₂ and CoX_0.25S_1.75 (X = O, Se, or Te) were magnetic, and Co atoms favoured ferromagnetic interaction. Except quasi-HM CoO_0.25S_1.75, quasi-metallic CoX_0.25S_1.75, CoX_0.0625S_1.9375, CoX_0.03125S_1.96875, and perfect metallic CoX_0.25S_1.75*, CoX_0.125S_1.875, were expected more suitable for use in supercapacitor and electrocatalyst. [ABSTRACT FROM AUTHOR]