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arXiv 2405.04239cond-mat.mtrl-sci
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二维材料中轨道磁化的高通量计算筛选

Orbital magnetization in two-dimensional materials from high-throughput computational screening

Martin Ovesen, Thomas Olsen

AI总结:

本研究通过高通量筛选计算了822种二维材料的轨道磁化,发现含5$d$元素材料具有显著轨道矩,且Hubbard修正与自旋-轨道耦合可导致未猝灭轨道矩及巨大磁各向异性,挑战了磁力定理的适用性。

摘要:

我们基于计算二维材料数据库(C2DB)计算了822种二维磁性材料的轨道磁化。对于含有5$d$元素的化合物,我们发现轨道矩约为0.3-0.5 $\mu_\mathrm{B}$,这表明在各类磁性建模及与实验比较中必须考虑这些轨道矩。研究还表明,轨道矩相对于自旋的取向大体遵循洪德规则(Hund's rule)的预测,而偏差可由晶体场引起的$d$带分裂解释——例如在重要的CrI$_3$案例中。最后,我们展示对于某些绝缘体,Hubbard修正可能导致大且完全未猝灭的轨道矩,这些轨道矩钉扎在晶格上而非自旋上,且这些矩可导致巨大的磁各向异性。此类未猝灭的基态仅能在同时包含Hubbard修正和自洽自旋-轨道耦合的密度泛函理论计算中获得,并在很大程度上否定了使用磁力定理计算磁各向异性的有效性。

英文摘要:

We calculate the orbital magnetization of 822 two-dimensional magnetic materials from the Computational 2D Materials Database (C2DB). For compounds containing 5$d$ elements we find orbital moments of the order of 0.3-0.5 $μ_\mathrm{B}$, which points to the necessity of including these in any type of magnetic modeling and comparison with experiments. It is also shown that the alignment of orbital moments with respect to the spin largely follows the predictions from Hund's rule and that deviations may be explained by the $d$-band splitting originating from the crystal field - for example in the important case of CrI$_3$. Finally, we show that for certain insulators, Hubbard corrections may lead to large and fully unquenched orbital moments that are pinned to the lattice rather than the spin and that these moments can lead to enormous magnetic anisotropies. Such unquenched ground states are only found from density functional theory calculations that include both Hubbard corrections and self-consistent spin-orbit coupling and largely invalidates the use of the magnetic force theorem for calculating magnetic anisotropies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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