Terahertz (THz) emission from a $\mathrm{Fe}(211)/\mathrm{Pt}(110)$ bilayer grown on $\mathrm{Mg}\mathrm{O}(110)$ is systematically investigated. The intensity of the emitted THz wave strongly depends on the magnetization (M) orientation, and the measured THz field is 11% larger for M||$\mathrm{Pt}[1\overline{1}0]$ than for M||Pt[001]. Using first-principles calculations combined with the superdiffusive spin-transport model, we reveal that the lattice distortion induced by epitaxial strain causes anisotropic behavior of the electronic conductance and spin Hall conductivity, which eventually lead to the aforementioned experimental observations. Our studies thus provide a route to modify THz emission utilizing the intrinsic crystal-structure degree of freedom.

中文翻译：

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aFe（211）/ Pt（110）双层的应变诱导各向异性太赫兹发射

太赫兹（THz）发射的 $铁（211）/铂（110）$ 双层生长 $镁\mathrm{Ø}（110）$被系统地调查。发射的太赫兹波的强度在很大程度上取决于磁化（M）方向，并且对于M || ，测得的太赫兹场大11％。$铂[\mathrm{1个}\overline{\mathrm{1个}}0]$比M || Pt [001]大。使用第一性原理计算与超扩散自旋传输模型相结合，我们揭示了由外延应变引起的晶格畸变会导致电子电导率和自旋霍尔电导率的各向异性，最终导致上述实验观察。因此，我们的研究提供了一种利用固有晶体结构自由度修改THz发射的途径。