The spin effects on electronic, optical and mechanical properties of new ferromagnetic chalcopyrite: YMnS2

In this study, magnetic and electronic nature, optical behavior, and elasticity properties of YMnS2 compound have been investigated by using density functional theory (DFT). The compound belongs to the chalcopyrite family having tetragonal crystal structure with 122 (I-42d) space group. Firstly, the optimization process has been done for ferromagnetic, antiferromagnetic, and paramagnetic orders to find most stable magnetic order and the formation energies have been determined. Negative formation energies prove that our compound is energetically synthesizable and structurally stable. For this compound, plotted energy change with respect to volume curves show that ferromagnetic order is most stable. It is understood from the electronic band structure obtained with Perdew-Burke-Ernzerhof functional within Generalized Graident Approximation, which has 1.27 eV band gap for spin-up orientation and metallic for spin-down orientation, so overall YMnS2 compound has a half-metallic nature. Moreover, the electronic band structure has been obtained with HSE06 functionals that indicates the half-metallic nature with 3.20 eV band gap in spin-up orientation and metallic nature in spin-down orientation. To understand optical properties, frequency dependent complex dielectric functions have been determined. Then, some optical properties have been investigated using the imaginary and real parts of the dielectric function. In addition to that, YMnS2 compound is mechanically stable according to Born-Huang stability criteria. Also, this new chalcopyrite compound is considered to be ductile, which is important for its use in technological applications.