electronic, optical, and thermoelectric properties of bafe2-xznxas2(x=0,1,2)orthorhombic polymorphs: dft study

Based on the calculations of density functional theory and generalized gradient approximation (gga), mechanical, electronic, optical and thermoelectric properti bafe2-xznxas2 (x=0,1,2) have been investigated in orthorhombic phase. for all three bafe2-xznxas2 (x=0,1,2), the energy curves have an equilibrium point in terms of their volume. for x=1 and x=2, the bonds take on an ionic shape. electronic calculations show that by applying the modified becke-johonsom (mbj) approximation, the x=2 compound is converted to a ptype semiconductor with a gap of 0.11 ev. however, magnetic behavior can be seen for the other two impurities. at x=2, the band structure illustrates a direct gap. optical diagrams display that the parts of the dielectric function exhibit strong metallic behavior for impurities x=0, 1, and also an optical gap can be detected. moreover, the seebeck coefficient provides that a good stability is observed in its behavior at room temperature onwards to reach the saturation limit of 200 μvk-1. additionally, the figure of merit reaches a saturation limit in the range of 0.6 to 0.7 at this temperature range.