斯托纳效应对磁子运动方程的贡献
Stoner contributions to the magnon equation of motion
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中文总结 AI 辅助
该研究基于线性响应理论推导无自旋轨道耦合下朗道阻尼磁子的运动方程，明确斯托纳连续区对磁子色散和寿命的影响，为实际材料磁子耦合常数估算提供方法。
中文摘要 AI 辅助
基于线性响应理论，我们推导了无自旋轨道耦合情况下朗道阻尼磁子准粒子的运动方程。该推导基于一组最小假设：即原胞内每个磁性原子对应一个集体本征模式，横向磁化率可通过这些本征模式对角化；且每个集体本征模式的谱由单个磁子共振主导。所得运动方程自然地将交换相互作用定义为平衡附近集体模式磁化的回复力。除磁交换外，该磁子运动方程还包含阻尼项与色散型准粒子质量，二者均源于电子-磁子耦合。以典型巡游铁磁体为例，这些项会使磁子色散红移，并在磁子进入斯托纳连续区时缩短磁子寿命。进一步假设集体磁子子空间与波矢无关，该磁子运动方程将成为具有明确磁位点的原子级方程。对于实际材料，可通过任意精度的能带理论近似动态横向磁化率来估算磁子耦合常数。
英文摘要
From linear response theory, we derive the equation of motion for Landau-damped magnon quasi-particles in absence of spin-orbit coupling. The derivation is based on a minimal set of assumptions, namely that the transverse magnetic susceptibility is diagonalized by one collective eigenmode per magnetic atom in the unit cell, and that the spectrum of each collective eigenmode is dominated by a single magnon resonance. The resulting equation of motion leads to a natural definition of the exchange interaction as the restoring force acting on the collective mode magnetization near equilibrium. In addition to magnetic exchange, the magnon equation of motion also contains a damping term and a dispersive quasi-particle mass, both originating from the electron-magnon coupling. The effect of these terms is illustrated for a prototypical itinerant ferromagnet, where they redshift the magnon dispersion and reduce the magnon lifetime as the magnon enters the Stoner continuum. By further assuming wave vector independence of the collective magnon subspace, the magnon equation of motion becomes atomistic with well defined magnetic sites. For real materials, one can approximate the magnon coupling constants using an arbitrary level of band theory for the dynamic transverse magnetic susceptibility.
发表机构
- Uppsala University（乌普萨拉大学）
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