AI 中文总结
研究拓扑绝缘体Bi$_2$Te$_3$与反铁磁多铁性BiFeO$_3$界面的自旋-电荷转换，利用非局部自旋输运装置，通过研究自旋输运厚度依赖性揭示拓扑表面态主导特征，展示了高效转换，突出Bi$_2$Te$_3$平台价值，为自旋基器件设计提供途径。
AI 中文摘要
拓扑绝缘体通过磁界面的自旋-电荷相互转换已被广泛研究，但其自旋-电荷转换的真实响应，尤其是在没有外部磁场的情况下，仍有待研究。本文利用非局部自旋输运装置，报道了在拓扑绝缘体Bi$_2$Te$_3$与反铁磁多铁性BiFeO$_3$中自旋-电荷转换的电场控制。系统研究了Bi$_2$Te$_3$和BiFeO$_3$界面自旋输运的厚度依赖性，揭示了双层系统中拓扑表面态主导的自旋输运特征。自旋-电荷转换在厚度大于10nm时保持稳健，但随厚度减小而迅速下降，在5nm时消失，这与平凡绝缘相的出现一致。这些结果表明自旋-动量锁定表面态在解耦状态下主导界面自旋输运。这项工作不仅展示了在完全绝缘磁界面上的高效自旋-电荷相互转换，还突出了溅射沉积的Bi$_2$Te$_3$作为将量子材料集成到器件中的高质量、可扩展平台。本文提出的非局部自旋输运方法为自旋-电荷转换提供了简单直接的证据，并为设计节能自旋基器件开辟了有效实用的途径。
英文摘要
Topological insulators have been explored extensively for spin-charge interconversion via magnetic interfaces, yet the true response of their spin-charge conversion, particularly in the absence of an external magnetic field, remains to be studied. Here, we report electric-field control of spin-charge conversion in the topological insulator Bi$_2$Te$_3$ with the antiferromagnetic multiferroic BiFeO$_3$, employing a nonlocal spin transport device. A systematic thickness dependence of the spin transport across the interface between Bi$_2$Te$_3$ and BiFeO$_3$ reveals a signature of topological surface-state-dominated spin transport in the bilayer system. The spin-charge conversion remains robust for thicknesses above 10 nm but falls rapidly with reducing thickness and vanishes at 5 nm. This is consistent with the hybridization-induced emergence of a trivial insulating phase, which is supported by the coherency factor estimated from the magnetoconductance of Bi$_2$Te$_3$. These results establish that spin-momentum-locked surface states dominate interfacial spin transport in the decoupled regime. Beyond presenting efficient spin-charge interconversion at an entirely insulating magnetic interface, this work also highlights sputter-deposited Bi$_2$Te$_3$ as a high-quality and scalable platform for integrating quantum materials into devices. The nonlocal spin transport approach presented here provides a simple and direct evidence of spin-charge conversion and opens an efficient and practical pathway toward designing energy-efficient spin-based devices.
Comments23 pages, 4 Figures
