Masseroni Michele, Gull Mario, Panigrahi Archisman, Jacobsen Nils, Fischer Felix, Tong Chuyao, Gerber Jonas D, Niese Markus, Taniguchi Takashi, Watanabe Kenji, Levitov Leonid, Ihn Thomas, Ensslin Klaus, Duprez Hadrien
Solid State Physics Laboratory, ETH Zürich, 8093, Zürich, Switzerland.
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Nat Commun. 2024 Oct 26;15(1):9251. doi: 10.1038/s41467-024-53324-z.
Van der Waals heterostructures provide a versatile platform for tailoring electronic properties through the integration of two-dimensional materials. Among these combinations, the interaction between bilayer graphene and transition metal dichalcogenides (TMDs) stands out due to its potential for inducing spin-orbit coupling (SOC) in graphene. Future devices concepts require the understanding of the precise nature of SOC in TMD/bilayer graphene heterostructures and its influence on electronic transport phenomena. Here, we experimentally confirm the presence of two distinct types of SOC - Ising (Δ = 1.55 meV) and Rashba (Δ = 2.5 meV) - in bilayer graphene when interfaced with molybdenum disulfide. Furthermore, we reveal a non-monotonic trend in conductivity with respect to the electric displacement field at charge neutrality. This phenomenon is ascribed to the existence of single-particle gaps induced by the Ising SOC, which can be closed by a critical displacement field. Our findings also unveil sharp peaks in the magnetoconductivity around the critical displacement field, challenging existing theoretical models.
范德华异质结构为通过二维材料的集成来定制电子特性提供了一个通用平台。在这些组合中，双层石墨烯与过渡金属二硫属化物（TMDs）之间的相互作用因其在石墨烯中诱导自旋轨道耦合（SOC）的潜力而脱颖而出。未来的器件概念需要了解TMD/双层石墨烯异质结构中SOC的精确性质及其对电子输运现象的影响。在这里，我们通过实验证实，当与二硫化钼接触时，双层石墨烯中存在两种不同类型的SOC——伊辛型（Δ = 1.55 meV）和 Rashba 型（Δ = 2.5 meV）。此外，我们揭示了在电荷中性时电导率相对于电位移场的非单调趋势。这种现象归因于由伊辛SOC诱导的单粒子能隙的存在，该能隙可由临界位移场关闭。我们的研究结果还揭示了临界位移场附近磁导率的尖锐峰值，这对现有的理论模型提出了挑战。
