Search

We report first-principles investigation on structural, electronic and magnetic properties of 3d transition metal element-doped rock-salt calcium selenide Ca 1 − x TMxSe (TM = V, Cr and Mn) at concentrations x = 0.0625, 0.125 and 0.25. We performed the calculations in the framework of the density functional theory (DFT) using the full-potential linearized augmented plane waves plus local orbitals (FP-LAPW+lo) method within the Wu–Cohen generalized gradient approximation (WC-GGA) for the structural optimization and the Tran–Blaha modified Becke–Johnson (TBmBJ) potential for the electronic and the magnetic properties. The computed spin-polarized band structures and densities of states show that Ca 1 − x CrxSe compounds at all studied concentrations are half-metallic ferromagnets with a complete spin polarization of 100% at Fermi-level while the Ca 1 − x VxSe and Ca 1 − x MnxSe are ferromagnetic semiconductors. The total magnetic moments for Ca 1 − x VxSe, Ca 1 − x CrxSe, and Ca 1 − x MnxSe show the integer values of 3 μ B , 4 μ B , and 5 μ B , respectively, with a major contribution of transition metal elements (TM) in the total magnetization. Also, we reported the calculated exchange constants N 0 α and N 0 β and the band edge spin splitting of the valence (Δ E v ) and conduction (Δ E c ) bands. The ferromagnetism of these compounds is due to the super-exchange and the double-exchange mechanisms in addition to the strong p–d exchange interaction. Therefore, the predicted results indicate that the diluted Ca 1 − x TMxSe (TM = V, Cr, Mn) compounds are suitable candidates for a possible application in the field of spintronic technology. [ABSTRACT FROM AUTHOR]

The structural, electronic and optical properties of the , and are studied by the spin-polarized first-principles calculation. The and are metals in tetragonal structures, while the in trigonal structure is half-metal with 100% spin polarization. The has the biggest static dielectric constant and static refractive index , which may be ascribed to the highest crystal symmetry. The maximum absorption peaks of the , and are located about 44 eV in the ultraviolet region, indicating these materials have good prospect for optoelectronic materials in the ultraviolet range. [ABSTRACT FROM AUTHOR]