Safeer C K, Ontoso Nerea, Ingla-Aynés Josep, Herling Franz, Pham Van Tuong, Kurzmann Annika, Ensslin Klaus, Chuvilin Andrey, Robredo Iñigo, Vergniory Maia G, de Juan Fernando, Hueso Luis E, Calvo M Reyes, Casanova Fèlix
CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain.
Solid State Physics Laboratory , ETH Zurich , 8093 Zurich , Switzerland.
Nano Lett. 2019 Dec 11;19(12):8758-8766. doi: 10.1021/acs.nanolett.9b03485. Epub 2019 Nov 6.
Efficient and versatile spin-to-charge current conversion is crucial for the development of spintronic applications, which strongly rely on the ability to electrically generate and detect spin currents. In this context, the spin Hall effect has been widely studied in heavy metals with strong spin-orbit coupling. While the high crystal symmetry in these materials limits the conversion to the orthogonal configuration, unusual configurations are expected in low-symmetry transition-metal dichalcogenide semimetals, which could add flexibility to the electrical injection and detection of pure spin currents. Here, we report the observation of spin-to-charge conversion in MoTe flakes, which are stacked in graphene lateral spin valves. We detect two distinct contributions arising from the conversion of two different spin orientations. In addition to the conventional conversion where the spin polarization is orthogonal to the charge current, we also detect a conversion where the spin polarization and the charge current are parallel. Both contributions, which could arise either from bulk spin Hall effect or surface Edelstein effect, show large efficiencies comparable to the best spin Hall metals and topological insulators. Our finding enables the simultaneous conversion of spin currents with any in-plane spin polarization in one single experimental configuration.
高效且通用的自旋到电荷电流转换对于自旋电子学应用的发展至关重要,自旋电子学应用强烈依赖于电产生和检测自旋电流的能力。在这种背景下,自旋霍尔效应已在具有强自旋轨道耦合的重金属中得到广泛研究。虽然这些材料中的高晶体对称性将转换限制为正交配置,但在低对称过渡金属二硫属化物半金属中预计会出现异常配置,这可以为纯自旋电流的电注入和检测增加灵活性。在这里,我们报告了在堆叠于石墨烯横向自旋阀中的碲化钼薄片中观察到的自旋到电荷转换。我们检测到由两种不同自旋取向的转换产生的两种不同贡献。除了自旋极化与电荷电流正交的传统转换外,我们还检测到自旋极化与电荷电流平行的转换。这两种贡献,可能来自体自旋霍尔效应或表面埃德尔斯坦效应,都显示出与最佳自旋霍尔金属和拓扑绝缘体相当的高效率。我们的发现使得在单一实验配置中能够同时转换具有任何面内自旋极化的自旋电流。