Ab-initio study of mechanical, half-metallic and optical properties of Mn2ZrX (X = Ge, Si) compounds

Abstract

The structural, elastic, electronic, magnetic and optical properties of Mn2 based full-Heusler alloys, Mn2ZrGe and Mn2ZrSi, were investigated by the first-principles full-potential linearized augmented plane wave (FP-LAPW) method in the framework of the Density Functional Theory. The AlCu2Mn-type structure was considered for both compounds. Based on E-V calculation, the ferromagnetic (FM) state was more stable than paramagnetic (PM) state. So, in the FM state the equilibrium lattice parameter was calculated as 5.995Å and 6.079Å for Mn2ZrSi and Mn2ZrGe respectively. The integer value 2.000µB is obtained for total magnetic moments of both compounds that is perfectly consistent with Slater-Pauling rule. These alloys in the minority spin channel have metallic property while in the majority spin channel, they have band gap that confirms their semiconductor properties. Elastic properties of the alloys such as bulk modulus B, shear modulus G, Young’s modulus E and Poisson's modulus ν were obtained. Also, optical properties like dielectric function, reflectivity, energy loss function, absorption coefficient and optical conductivity were calculated.