Magnetic ground state and optoelectronic properties of GdMg, GdMg2 and GdMg3 investigated by GGA+U calculations

Abstract

The present work is a study of the magnetic ground state and optoelectronic properties of GdMg, GdMg2 and GdMg3 using FP-(L)APW + lo method as implemented in WIEN2k code. GGA-PBE has been used as exchange-correlation functional for the prediction of structural properties as well as the most stable magnetic phase. The obtained results are in agreement with the previous results; they indicate that at the ground state, GdMg is ferromagnetic whereas GdMg2 and GdMg3 are antiferromagnetic. To ensure a suitable accuracy for the optoelectronic study of these compounds, the effective Coulomb interaction term “U” between 4f-electrons of Gadolinium atom was determined by constrained LDA “cLDA”. The total and partial magnetic moments values confirm the results of the most stable magnetic phase. The electronic study of these compounds indicates that they are all metallic. The optical properties were studied after the determination of the dielectric function of the different compounds taking into account the intra-band transitions which have a significant contribution in metals. Several optical magnitudes have been determined including the possible inter-band and intra-band electronic transitions as well as the evolution of the optical absorption and the refractive index under the effect of excitation by photon energy.