DFT + U and QTAIM Studies of Elastic, Magnetic, Bonding, and Optoelectronic Behaviors of RbUO3

Abstract

Several experimental works have shown that RbUO3 has antiferromagnetic behavior with G-type ordering. In this work, E = F(V) curves for the different spin magnetic ordering (NM, FM, A-AFM, C-AFM, and G-AFM) were analyzed, from which it was confirmed that G-AFM is the most stable magnetic order. The found lattice parameter values of RbUO3 are very close to those found both in theory and in experimental. The obtained elastic constant values have confirmed the mechanical stability of RbUO3. The studies of the directional dependence of Young’s modulus and the found value of the universal elastic anisotropy index have shown that this compound is largely anisotropic. The electronic properties were studied taking into account the strong correlation between 5f-U electrons. The found results have shown that RbUO3 has an indirect band gap of XV-ΓC nature. The detailed study of bonding was carried out using QTAIM theory from which the number and positions of the different bonds were located, and it was found that the ionic character is predominant. The electronic transitions and optical absorption were respectively studied by the analysis of the variation of the dielectric function and that of the absorption coefficient.