Probing the structural, opto-electronic, mechanical, and thermoelectric properties of novel lead free semiconductor double perovskites Rb2MgMnX6 (X = Cl, Br, I): First principle study

Halide Double perovskites are promising materials for generating green energy that could fulfill worldwide desires for addressing energy scarcity crises. The structural stabilities of the scrutinized materials have been ascertained from the simulated formation energy and Goldsmith tolerance factor. On the other hand, the demonstrated Pughs ratio depicts the ductile nature of the studied materials. The electronic band structure and density of states are determined using Generalised gradient approximation and modified Becke-Johnson potential. The calculated magnetic moment is 5 μB, mainly due to the contribution of the d -Mn atom. Our obtained values show a significant light absorption in the visible range, which illustrates the materials potential for use in optoelectronic devices. The thermoelectric properties have also been investigated regarding Seebeck coefficient, electrical conductivity, thermal conductivity, and figure of merit zT.Graphical abstractWith deeper analysis on a ground level, the electronic charge density shown in Fig.3offers a substantial and fascinating study of the nature of hybridization among the various atomic orbitals. Here, to visualize chemical bonding, we looked at charge density plots in the (110) plane. As a result, this study includes the covalent nature of the bond between chlorine and manganese as well as the ionic nature of the bond between rubidium and chlorine. In Rb2MgMnBr6and Rb2MgMnI6a similar type of bonding has also been found. Therefore, the entire study indicates that these semiconductor alloy systems have well-maintained polar covalent bonding, which is a combination of covalent and ionic bonds.