Strongly anisotropic spin relaxation in graphene-transition metal dichalcogenide heterostructures at room temperature
Strongly anisotropic spin relaxation in graphene-transition metal dichalcogenide heterostructures at room temperature
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DOI：
10.1038/s41567-017-0019-2
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发表时间：
2018-03-01
期刊：
影响因子：
19.6
通讯作者：
Valenzuela, Sergio O.
中科院分区：
文献类型：
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作者：
Antonio Benitez, L.;Sierra, Juan F.;Valenzuela, Sergio O.
预测了当石墨烯与半导体过渡金属二卤化物连接时，它的自旋-轨道耦合作用会有很大的增强。已经报道了这种增强的特征，但这些系统中自旋弛豫的性质仍然不清楚。在这里，我们明确地展示了由石墨烯和二硫化钨或二硫化钼(WS2，MoS2)组成的双层异质结构中的各向异性自旋动力学。我们观察到，自旋寿命随自旋取向的不同而变化一个数量级，当自旋指向石墨烯平面外时，自旋寿命最大。这表明，过渡金属二卤化物中强烈的自旋-谷耦合被压印在双层中，并被传播的自旋感受到。这些发现为探索耦合的自旋谷现象提供了丰富的平台，并提供了基于二维材料中自旋弛豫各向异性的新的自旋操纵策略。
A large enhancement in the spin-orbit coupling of graphene has been predicted when interfacing it with semiconducting transition metal dichalcogenides. Signatures of such an enhancement have been reported, but the nature of the spin relaxation in these systems remains unknown. Here, we unambiguously demonstrate anisotropic spin dynamics in bilayer heterostructures comprising graphene and tungsten or molybdenum disulphide (WS2, MoS2). We observe that the spin lifetime varies over one order of magnitude depending on the spin orientation, being largest when the spins point out of the graphene plane. This indicates that the strong spin-valley coupling in the transition metal dichalcogenide is imprinted in the bilayer and felt by the propagating spins. These findings provide a rich platform to explore coupled spin-valley phenomena and offer novel spin manipulation strategies based on spin relaxation anisotropy in two-dimensional materials.