Predictive Study of the Rare Earth Double Perovskite Oxide Ba2ErReO6 and the Influence of the Hubbard Parameter U on its Half-Metallicity.

In this paper, we have studied and carried out a theoretical calculation using the full-potential linearized augmented plane-wave method (FP-LAPW), based on density functional theory (DFT) and implemented in the wien2k program to investigate the structural, electronic, and magnetic properties of Ba₂ErReO₆ material, within the generalized gradient approximation (GGA) and generalized gradient approximation with effective Hubbard U parameter (GGA + U). According to the electronic properties and according to the GGA approximation, the results show that our material Ba₂ErReO₆ has a metallic character with integral magnetic moment of 5.1 µB; however, through employing the GGA + U method, the material Ba₂ErReO₆ radically changes in nature due to the fact that it presents a half-metallic character with a direct band gap at Γ-Γ direction in spin down channel and this for values of U ≥ 2 eV; in addition, we see that the greater the Hubbard coefficient U, the greater the energy gap of the material in its semi-conducting nature (in the spin down channel) until reaching the value of 1.96 eV corresponding to a value of 8 eV for the Hubbard coefficient U. This is a predictive study of the double perovskite compound Ba₂ErReO₆ based on rare earths Er and therefore constitutes a serious reason for further theoretical investigations as well as adequate experiments and this for very useful and widespread applications such as spintronic, high-performance electronic devices, and optic applications. [ABSTRACT FROM AUTHOR]