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The structural, elastic, magnetic and electronic properties of titanium-based alloys TiX2 (X = Cr, Mn) are investigated by the first-principles calculations based on density functional theory using the Vienna ab-initio simulation code. The lattice constants of TiX2 (X = Cr, Mn) alloys are optimized for various possible structures such as hexagonal, tetragonal and orthorhombic. TiX2 (X = Cr, Mn) alloys are highly stable in hexagonal structure with the space group P63/mmc at ambient pressure. A pressure-induced structural phase transition from hexagonal structure to the tetragonal structure is observed in TiCr2 at 443.3 GPa and in TiMn2 hexagonal structure to orthorhombic structure is at 295.05 GPa. The electronic structure shows that TiX2 (X = Cr, Mn) alloys are metallic in nature at all pressures. The magnetic property of nonmagnetic TiX2 (X = Cr, Mn) alloys are analyzed by doping with ferromagnetic materials (Fe, Co and Ni) using the stoichiometries of TiX 2 − z Y z (X = Cr, Mn; Y = Fe, Co and Ni; z = 0.5,1,1.5). It is seen that the magnetic moment is induced by the substitution of ferromagnetic materials with TiX2 alloys. [ABSTRACT FROM AUTHOR]

Transparent conducting oxides (TCOs) of semiconductor family gained significant attention due to increasing trends in the optoelectronic and thermo-physical applications. In current work, we reported electronic, optical, transport and thermodynamical properties of spinel oxides ZnGaO 2 , [ZnGaO 2 :Mn3+ and [ZnGaO 2 :Rh3+ compounds. Based on DFT, we employed first-principles calculations implemented in Wien 2k using the modified-Becke-Johnson (mBJ) on parent spinel and generalized-gradient-approximation plus Hubbard potential U (GGA + U) on doped materials, respectively. The calculated band structure shows insulating nature of parent compound, while doped material observed semiconducting nature contains direct band gap for both spin channels with band gaps of [ZnGaO 2 :Mn3+ (0.59 up, 2.4 eV dn) and [ZnGaO 2 :Rh3+ (2.1 eV up/dn) respectively. The electronic and optical results reveal that hybridization occurred mainly due to O-p/Zn, Mn-d, Rh-d and Ga-s orbitals. It is analyzed that Mn-doped material shows good absorption in the visible region while other are good in UV region. The effective masses of spinel oxides are also computed at high symmetry directions hence varied nonlinearly with the doping. The stability of materials is checked by calculating formation energies which indicate Mn-doped spinel oxide is most stable as that of others. The thermoelectric properties of spinel oxides were carried out by Post-DFT (Boltztrap) calculations. Large values of Seebeck coefficient and power factor of Mn-doped spinel oxide indicate that this material can be used for thermoelectric devices. The thermodynamical properties are calculated by quasi-harmonic Debye model implemented in GIBBS 2 code. Moreover, the pressure and temperature dependence of all (TD) parameters of investigated spinel oxides are analyzed using quasi-harmonic Debye model. Image 1 • We investigated structral, optoelectronic and tranport properties of spinel oxides Fe 3 BO 6 and Rh 0.08 Fe 0.92 BO 6 compounds. • The approximation used for these calculations was generalized gradient plus Hubbard potential (GGA+U). • The band structure of parent compound for spin up shows insulating nature while other channel is semiconducting nature (4.181 eV Up/2.41 eV Dn). • The optical dispersion exhibits strong absorption in the UV region, for both materials. • The transport parameters are computed by Post-DFT approximations based on rigid band approach in Boltzmann code. [ABSTRACT FROM AUTHOR]