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The structural, electronic, and half-metallic ferromagnetic properties of ordered zinc blende Al 1−x Mn x P diluted magnetic semiconductors with concentrations (x = 0.0625, 0.125, and 0.25) are studied using firstprinciple calculations of density functional theory in order to seek out the possibility to use these materials for the spin injection in the field of spintronic applications. The electronic structures of Al 1−x Mn x P at all concentrations exhibit a half-metallic ferromagnetic behavior with 100 % magnetic spin polarization and half-metallic gap. While, the analysis of partial densities of states reveals that strong hybridization between 3p (P) and 3d (Mn) partially filled states dominates the gap, which stabilizes the ferromagnetic state configuration associated with double-exchange mechanism. Also, the magnetic proprieties prove an integer total magnetization of 4 u B that confirms the half-metallic ferromagnetic feature of Al 1−x Mn x P compounds.

Using the first-principle calculations of density functional theory within the (FP-LAPW) method, we have investigated the structural, electronic and optical properties of Bi 2 Te 3-x Se x alloys with compositions x = 0, 1, 2 and 3 of Se. The generalized gradient approximation functional of Wu and Cohen (GGA-PBE) is used to calculate ground state structural parameters of Bi 2 Te 3-x Se x , which are in good agreement with theoretical and experimental data. The electronic band structures and optical constants have been improved with Tran-Blaha modified Becker-Johnson (TB-mBJ) parameterization scheme. Also, we have analyzed in detail the performance of dielectric function, refractive index, reflectivity and optical conductivity of these alloys. Our results show that Bi 2 Te 3-x Se x alloys are promising candidates for optoelectronic applications especially in the Infrared and visible fields. Bi 2 Te 3-x Se x materials have a direct band gap and can be tuned from 0.1706 eV to 0.7819 eV by varying In composition so emission was tunable from 1.58 to 7.26 micrometers (infrared field), in addition for their direct band gap and in view of their attractive optical properties such conductivity, absorption and reflectivity these materials is considered as promising materials for optoelectronic applications.

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