蜂巢反铁磁体中动量依赖的进动与章动自旋泵浦
Momentum-dependent precessional and nutational spin pumping in a honeycomb antiferromagnet
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中文总结 AI 辅助
本研究通过将自旋惯性纳入LLG方程，计算了蜂巢反铁磁体MnPS$_3$的动量分辨进动与章动自旋泵浦，发现两者动量依赖互补，且章动电流受惯性弛豫时间强调控，为区分章动与进动提供新方法。
中文摘要 AI 辅助
亚皮秒时间尺度上的超快磁性惯性动力学产生了额外的高频太赫兹章动共振。本文通过将自旋惯性纳入Landau-Lifshitz-Gilbert方程，研究了二维蜂巢反铁磁体中的动量分辨自旋泵浦。利用包含$J_1$-$J_2$-$J_3$交换相互作用的微观双子格模型，我们计算了整个布里渊区内的进动和章动磁振子谱及其相应的子格内和子格间自旋泵浦贡献。对于代表MnPS$_3$的参数，我们发现两个自旋泵浦通道具有显著的互补动量依赖性：进动电流在$\Gamma$点附近被强烈抑制（0.01%），并向布里渊区边界增加（在$K$点为100%，在$M$点为87%），而章动电流在$\Gamma$点附近最大（100%），并向边界减小（在$K$点为68%，在$M$点为69%）。这种对比鲜明的动量依赖性为区分自旋章动与常规进动运动提供了手段。我们进一步证明，章动自旋泵浦电流受到惯性弛豫时间$\eta$的强烈控制，而进动电流对$\eta$的依赖性相对较弱。在小$\eta$区域，我们的解析结果表明，子格内章动自旋泵浦电流表现出$1/\eta^3$的首阶依赖性。自旋泵浦响应也可以通过交换相互作用强度和磁矩进行调控。我们关于自旋泵浦磁场依赖性的进一步结果表明，章动自旋泵浦电流的比例随磁场强度增加而增大，而相应的进动电流比例则减小。
英文摘要
The ultrafast magnetic inertial dynamics on subpicosecond timescales generate an additional high-frequency terahertz nutational resonance. Here, we investigate momentum-resolved spin pumping in a two-dimensional honeycomb antiferromagnet by incorporating spin inertia into the Landau-Lifshitz-Gilbert equation. Using a microscopic two-sublattice model with $J_1$-$J_2$-$J_3$ exchange interactions, we calculate the precessional and nutational magnon spectra and their corresponding intra- and inter-sublattice spin pumping contributions throughout the Brillouin zone. For parameters representative of MnPS$_3$, we find a pronounced complementary momentum dependence of the two spin pumping channels: the precessional current is strongly suppressed around the $Γ$ point ($0.01\%$) and increases towards the Brillouin zone boundary ($100\%$ at $K$ and $87\%$ at $M$), whereas the nutational current is largest near $Γ$ ($100\%$) and decreases towards the boundary ($68\%$ at $K$ and $69\%$ at $M$). This contrasting momentum dependence provides a means of distinguishing spin nutation from conventional precessional motion. We further demonstrate that the nutational spin pumping current is strongly controlled by the inertial relaxation time $η$, in contrast to the comparatively weak $η$ dependence of the precessional current. In the small-$η$ regime, our analytical results show that the intra-sublattice nutational spin pumping current exhibits a leading-order dependence of $1/η^3$. The spin pumping response can also be tuned through the exchange interaction strengths and magnetic moment. Our further results on the magnetic field dependence of spin pumping reveal that the ratio of nutational spin pumping current increases with magnetic field strength, whereas the corresponding precessional counterpart decreases.
发表机构
- Indian Institute of Technology (ISM) Dhanbad（印度技术学院（ISMD）丹巴德）
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