Abstract
Calculated band structure (mBJ) of (a) Mg3N2 (b) Mg3P2 (c) Mg3As2 (d) Mg3Sb2 and (e) Mg3Bi2.
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•Mg3X2 (X=N, P, As, Sb, Bi) have gained importance due to their fascinating physical properties.•These are direct bandgap materials.•These compounds show high absorption in the visible and low frequency ultraviolet regions.•Electrical conductivity (σ) per relaxation time (τ) are maximum for Mg3N2.•These are suitable for optoelectrics and thermoelectric applications.
Magnesium pnictides Mg3X2 (X=N, P, As, Sb, Bi) have gained importance due to their fascinating physical properties. These compounds have been mainly studied from the structural and electronic band structure aspects. In this work, the structural, electronic, optical and thermoelectric properties of Mg3X2 (X=N, P, As, Sb, Bi) compounds have been investigated by using density functional theory. The crystal structure of the compounds is optimized through Wu-Cohen generalized gradient approximation (WC-GGA). Modified Becke-Johnson exchange potential predicted the bandgaps larger than the WC-GGA and Englo-Vosko GGA. All the compounds are predicted to be direct bandgap. Bandgap of the compounds decreased by changing the cation from N to Bi. Optical properties of the compounds are described in details. The thermoelectric properties of the compounds are also characterized. On the basis of suitable direct bandgap nature and good thermoelectric coefficients these materials are potential candidates for the optoelectronics and thermoelectric applications.