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

Khang D. Pham, M. Batouche, D.E. Si Mohammed, T. Seddik, Tuan V. Vu, Dat D. Vo, Nguyen N. Hieu, O.Y. Khyzhun



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 MgSc2Se4 are direct-gap semiconductors. The optical features of MgSc2S4 and MgSc2Se4 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 C12−C44 of 1.60 and −4.485 GPa (for MgSc2Se4); 1.61 and −3.655 GPa (for MgSc2S4). MgSc2S4 and MgSc2Se4 reveal similar ZTe values. The obtained properties of MgSc2X4 (X ​= ​S; Se) are well confirmed by experimental results.

Graphical abstract

Weighted band structures of MgSc2S4 and MgSc2Se4 as obtained by TB-mBJ.

Image 1

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