Study of optoelectronic, thermoelectric and induced half-metallicity in Wurtzite ZnS via codoped (Eu, Cr): A DFT method

Abstract

Based on the Density Functional Theory (DFT), we have successfully examined the wurtzite sulfide (ZnS) codoped with the couple (Eu, Cr). This study calculates the electronic, magnetic, optical, and thermoelectric (TE) properties using the GGA and GGA + U methods. Our results find that the ferromagnetic alignment of spin is more stable than its antiferromagnetic coupling. Most notably, a half-metallic behaviour is observed in the codoped material, exhibiting 100 % spin polarization at the Fermi level. However, the origins of ferromagnetism in the complex Zn_1-2xEu_xCr_xS, x = 0.0625, are due to hybridization between S-3p, Cr-3d, and Eu-4f states in the case of the GGA approximation and p-f hybridization in the case of GGA + U. The insertion of double impurities leads to a compound with a large half-metallic gap. The optical simulation of ferromagnetic alloy reveals a high absorption coefficient at the ultraviolet spectrum level and a low reflectivity in the visible range. Furthermore, the calculation of the figure of merit ZT ∼ 1 proves that we have an efficient material for converting thermal energy into electricity. All these qualities combine to make ${\mathrm{Zn}}_{1-2x}{\mathrm{Eu}}_x{\mathrm{Cr}}_{x}S$ a half-metallic ferromagnetic material efficient for spintronic, optoelectronic, and thermoelectric applications.