Data archive of "All-electrical creation and control of spin-galvanic signal in graphene and molybdenum ditelluride heterostructures at room temperature"

By using 2D materials heterostructures it is possible to exploit the properties of both materials at the interface, for instance, spin-dependent transport for application in spintronic devices. Here, using a heterostructure of MoTe2/Graphene the authors demonstrate a proximity induced spin-galvanic effect which can be controlled by the gate voltage. The ability to engineer new states of matter and control their spintronic properties by electric fields is at the heart of future information technology. Here, we report a gate-tunable spin-galvanic effect in van der Waals heterostructures of graphene with a semimetal of molybdenum ditelluride at room temperature due to an efficient spin-charge conversion process. Measurements in different device geometries with control over the spin orientations exhibit spin-switch and Hanle spin precession behavior, confirming the spin origin of the signal. The control experiments with the pristine graphene channels do not show any such signals. We explain the experimental spin-galvanic signals by theoretical calculations considering the spin-orbit induced spin-splitting in the bands of the graphene in the heterostructure. The calculations also reveal an unusual spin texture in graphene heterostructure with an anisotropic out-of-plane and in-plane spin polarization. These findings open opportunities to utilize graphene-based heterostructures for gate-controlled spintronic devices.

借助二维材料异质结（2D materials heterostructures），可充分利用界面处两种材料的协同特性，例如可应用于自旋电子学器件（spintronic devices）的自旋依赖输运（spin-dependent transport）现象。本研究以二碲化钼/石墨烯（MoTe₂/Graphene）异质结为研究对象，观测到可通过栅极电压（gate voltage）调控的邻近诱导自旋整流效应（spin-galvanic effect）。通过电场调控物质新物态及其自旋电子学特性的能力，是未来信息技术的核心所在。本研究报道了室温下，石墨烯与半金属（semimetal）二碲化钼构建的范德华异质结（van der Waals heterostructures）中，经由高效自旋-电荷转换（spin-charge conversion）过程实现的栅极可调自旋整流效应。通过调控自旋取向（spin orientations）并在不同器件几何构型（device geometries）下开展测量，实验观测到自旋开关（spin-switch）与Hanle自旋进动（Hanle spin precession）行为，证实了该信号的自旋起源。针对本征石墨烯（pristine graphene）沟道的对照实验未观测到此类信号。本研究结合理论计算，考虑异质结中石墨烯能带内由自旋轨道（spin-orbit）诱导的自旋劈裂（spin-splitting）效应，对实验观测到的自旋整流信号进行了解释。计算结果同时揭示了石墨烯异质结中一种特殊的自旋纹理（spin texture），其自旋极化呈现面内（in-plane）与面外（out-of-plane）各向异性（anisotropic）特征。上述研究成果为将石墨烯基异质结应用于栅极调控型自旋电子学器件提供了可能。