First principle study of structural, electronic, ferromagnetic, mechanical and thermoelectric properties of ZnMn2X4 (X = S and Se) spinels

Abstract

The structural, mechanical, electro-magnetic and transport attributes of ZnMn2X4 (X = S and Se) spinels are explored by density functional theory (DFT). The stability in structures are affirmed by negative formation energy. Moreover, structural optimizations have suggested studied compounds are stable in ferromagnetic phase. This phenomenon is also endorsed in electronic properties by band structures and density of states. In magnetic properties, ferromagnetic nature is discussed in detail by pd hybridization process, double exchange model, exchange energies and exchange constants. It is found that negative exchange constant N0β lower the ground energy of system which is in conformity to the double exchange mechanism. Furthermore, the magnetic moment shifting observed at Mn site to nonmagnetic sites (Zn, S/Se) is due to quantum coupling of electrons. Finally transport properties are evaluated by finding electrical conductivity, thermal conductivity, Seebeck coefficient and power factor. All these parameters are in support of the compounds, which suggest novel spintronic applications.