AI 中文总结
本研究探究磁性滑动铁电体中的分数自旋铁电体，提出层间滑动可产生滑动自旋电流的新机制，通过多种实验已证实或合成的材料验证了该机制，为纯自旋电流的全电产生提供了新途径并预测了实验候选材料。
AI 中文摘要
我们研究磁性滑动铁电体（SFEs）中的分数自旋铁电体（FSFE），其铁电极化翻转不仅由面外电极化的反转表征，还由面内分数自旋电子极化的变化表征。我们表明，FSFE中的层间滑动可自然产生一种对称性保护的纯自旋电流，此处称为滑动自旋电流。其内在机制为：在翻转过程中，价电子和离子对面内电荷转移的贡献相互抵消，而仅源于价电子的面内自旋转移则持续存在，从而形成纯自旋电流。我们在多种材料候选体系中验证了该设想，包括实验已证实为磁性SFE的H堆叠双层CrI₃，以及已实验合成的R堆叠双层2H-VX₂（X=S、Se、Te）。对于约1纳秒的典型翻转时间，双层CrI₃和VX₂的自旋电流密度估计值分别达10⁹ (ℏ/2e)A/m²和10⁸ (ℏ/2e)A/m²。这意味着通过施加周期性面外电场，可在磁性SFEs中产生显著的交变自旋电流。因此，本研究提出了一种极具吸引力的纯自旋电流全电产生新机制，并预测了可供实验验证的具体现实材料。
英文摘要
We investigate the fractional spin ferroelectric (FSFE) in magnetic sliding ferroelectrics (SFEs), where ferroelectric switching is characterized not only by the reversal of the out-of-plane electric polarization but also by a variation of fractional in-plane spin electronic polarization. We show that interlayer sliding in FSFEs can naturally lead to a symmetry-protected pure spin current, termed the sliding spin current here. The underlying mechanism is that, during switching, the contributions of valence electrons and ions to the in-plane charge transfer cancel each other, whereas the in-plane spin transfer, which stems solely from valence electrons, persists, leading to a pure spin current. We demonstrate our ideas in various material candidates, including $H$-stacked bilayer CrI$_3$, whose few-layer form has been experimentally confirmed to be a magnetic SFE, and $R$-stacked bilayers $2H$-V$X_2$ ($X=$ S, Se, Te), which have been experimentally synthesised. For a typical switching time of about $1$ ns, the estimated spin-current densities for bilayer CrI$_3$ and V$X_2$ reach $10^9 (\hbar/2e)\mathrm{A/m^2}$ and $10^8 (\hbar/2e)\mathrm{A/m^2}$, respectively. This means that by applying a periodic out-of-plane electric field, a significant alternating spin current can be generated in magnetic SFEs. Thus, our findings propose a compelling new mechanism for the all-electrical generation of pure spin current, and predict concrete realistic materials for experimental verification.
