A relatively simple model based on the coexistence of spin and electron subsystems is proposed for a description of magnetization processes in metallic rare earth tetraborides. The model takes into account the Ising interaction between the localized spins, the Hubbard interaction between the itinerant electrons, and the Ising interaction between electron and spin subsystems. To solve this model, a combination of small cluster exact diagonalization calculations and quantum Monte Carlo simulations is used. Particular attention is paid to a description of correlation effects (the Hubbard interaction) on formation and stabilization of magnetization plateaus with fractional magnetizations. It is shown that the Hubbard interaction significantly stabilizes the 1/2 magnetization plateau and simultaneously suppresses the 1/3 magnetization plateau, in accordance with experimental measurements in rare earth tetraborides.

提出了一种基于自旋子系统和电子子系统共存的相对简单的模型，用于描述金属稀土四硼化物中的磁化过程。该模型考虑了局部自旋之间的Ising相互作用，流动电子之间的Hubbard相互作用以及电子与自旋子系统之间的Ising相互作用。为了求解该模型，结合使用了小簇精确对角化计算和量子蒙特卡洛模拟。特别要注意对分数磁化强度的磁化高原的形成和稳定的相关效应（哈伯德相互作用）的描述。结果表明，哈伯德相互作用显着稳定了1/2的磁化平台，同时抑制了1/3的磁化平台，