The computational modeling within a density functional theory was applied for simulations of electronic spectra and calculations of structural and energy characteristics of the cubic double perovskite oxides Sr₂Mg_1−xNi_xMoO_6–δ, where x = 0, 0.5, and 1. The oxygen stoichiometric molybdates are antiferromagnetic semiconductors with an energy gap near 2 eV. The energy-based arguments show that anti-site cation disorder may contribute to the structural stability of the molybdates. It is found that nickel doping is favorable for mitigated chemical expansion. The replacement of magnesium by nickel is accompanied by the contribution of Ni3d states to the valence band while leaving hybrid Mo4d-O2p states in the conduction band virtually unchanged. It is shown that the compounds under study are thermodynamically unstable in heavily reducing conditions which is confirmed by experimental results. The appearance of oxygen deficiency in Sr₂Mg_1−xNi_xMoO_6–δ results in the formation of oxygen vacancy associated donor states near the bottom of the conduction band and the transition from the intrinsic to degenerate semiconductor. It is suggested that the influence of nickel dopants on the energy and density of the donor states may help to explain variations of the conducting properties with doping level.

密度泛函理论中的计算模型用于模拟电子光谱以及计算立方双钙钛矿氧化物 Sr ₂ Mg _1-x Ni _x MoO _6-δ的结构和能量特性，其中 x = 0、0.5 和 1。氧化学计量的钼酸盐是反铁磁半导体，能隙接近 2 eV。基于能量的论点表明，反位阳离子无序可能有助于钼酸盐的结构稳定性。发现镍掺杂有利于减轻化学膨胀。用镍替代镁伴随着 Ni3d 态对价带的贡献，而导带中的混合 Mo4d-O2p 态几乎没有变化。实验结果表明，所研究的化合物在严重还原条件下是热力学不稳定的。Sr ₂ Mg _1−x Ni _x MoO _6–δ缺氧的出现导致在导带底部附近形成与氧空位相关的供体态，以及从本征半导体到简并半导体的转变。建议镍掺杂剂对施主态能量和密度的影响可能有助于解释导电性能随掺杂水平的变化。