声子-磁子散射对反铁磁和铁磁氧化物热输运的影响

中文摘要 AI 辅助

声子-磁子耦合已在铁磁体中得到了广泛研究，而其微观机制在反铁磁体中仍了解较少。在此，我们结合第一性原理计算与自旋-晶格动力学，研究反铁磁NiO和MnO中的声子-磁子相互作用及其对热输运的影响，并将其与具有相同晶体结构的铁磁EuO进行对比。格林-久保和谱能量密度分析表明，自旋动力学降低了声子热导率和寿命，其中MnO中的效应最强。激发谱的比较表明，自旋诱导的声子散射对声子和磁子能量尺度的相对大小敏感，而MnO和EuO的对比行为进一步凸显了磁有序的作用。一个简化的相空间模型进一步说明，在声子和磁子能量尺度相当的情况下，反铁磁情况可以支持比铁磁情况更大的声子-磁子散射相空间，这表明存在更多运动学允许的散射通道。这些结果确定了激发能量尺度和磁有序是控制磁性材料中声子-磁子散射的关键因素。

英文摘要

Phonon--magnon coupling has been extensively studied in ferromagnets, whereas its microscopic mechanisms in antiferromagnets remain less understood. Here, we combine first-principles calculations with spin--lattice dynamics to investigate phonon--magnon interactions and their impact on thermal transport in antiferromagnetic NiO and MnO, which are put in contrast to the ferromagnetic EuO with an identical crystal structure. Green--Kubo and spectral energy density analyses show that spin dynamics reduce phonon thermal conductivity and lifetimes, with the strongest effects in MnO. Comparison of the excitation spectra indicates that spin-induced phonon scattering depends sensitively on the relative phonon and magnon energy scales, while the contrasting behavior of MnO and EuO further highlights the role of magnetic order. A simplified phase-space model further illustrates that, for comparable phonon and magnon energy scales, the antiferromagnetic case can support a larger phonon--magnon scattering phase space than the ferromagnetic case, suggesting a greater number of kinematically allowed scattering channels. These results identify excitation energy scales and magnetic order as key factors governing phonon--magnon scattering in magnetic materials.

发表机构

• University of California, Santa Barbara（加州大学圣塔芭芭拉分校）

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