Ab initio study of the structural, electronic, optical and elastic properties of promising optoelectronic and thermoelectric compounds MgSc2X4 (X = S; Se)

In this paper, we study theoretically the structural, electronic, optical, elastic and thermoelectric properties of MgSc2X4 (X = S; Se) compounds using first-principles calculations. The calculated band structure reveals that MgSc2S4 and MgSc2S4 are direct-gap semiconductors. The optical features of MgSc2S4 and MgSc2S4 as functions of photon energy were calculated for energy range of 0-20 eV. MgSc2X4 (X = S; Se) are promising optoelectronic, and thermoelectric compounds whose absorption rates can reach 4 orders of magnitude in the visible range, and 6 orders of magnitude in ultraviolet range. Both chalcogenides possess high brittleness with the Pugh's ratio (B/G), and Cauchy pressure C-12 - C-44 of 1.60 and -4.485 GPa (for MgSc2S4); 1.61 and -3.655 GPa (for MgSc2S4). MgSc2S4 and MgSc2S4 reveal similar ZT, values. The obtained properties of MgSc2X4 (X = S; Se) are well confirmed by experimental results.