Screening the structural, optoelectronic and thermoelectric features of novel inverse perovskites X3MgNa (X= Cl, Br and I): A theoretical investigation

Abstract

The structural, optoelectronic, and transport features of novel X3MgNa (X = Cl, Br, and I) antiperovskites compounds are revealed by using the density functional theory. The structural stability of all of the compounds under consideration has been verified by using the Birch-Murnaghan equations of states, which indicate that all compounds have structural stability due to ground-state energy levels being negative. The electronic band structure and TDOS results reveal that the electronic band gap of Cl3MgNa is 4.22 eV, Br3MgNa is 2.18 eV, and I3MgNa is zero eV. The partial density of state PDOS results demonstrate that the formation of the conduction and valence bands is due to the hybridization of Cl-3p, Br-4p, Na-3p, and I-5p states. In terms of optical results, reverse perovskite with Br as a cation has shown much better optical conductivity in the ultraviolet range. Therefore, Br3MgNa is a potential candidate among all the compounds for optoelectronic-based applications. The Boltztrap code, which is patched with WEIN2K code, has been used to compute the thermoelectric characteristics of the examined compounds. Br3MgNa has a greater power factor, a high electrical conductivity, and a figure-of-merit; ZT approaches unity, indicating a promising option for thermoelectric applications.