Quantum Hall Effect Measurement of Spin–Orbit Coupling Strengths in Ultraclean Bilayer Graphene/WSe₂ Heterostructures

Journal Article · Tue Sep 17 00:00:00 EDT 2019 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.9b02445· OSTI ID:1802136

Wang, Dongying ^[1]; Che, Shi ^[2]; Cao, Guixin ^[2]; Lyu, Rui ^[3]; Watanabe, Kenji ^[4]; Taniguchi, Takashi ^[4]; Lau, Chun Ning ^[2]; Bockrath, Marc ^[2]

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1. The Ohio State Univ., Columbus, OH (United States); OSTI
2. The Ohio State Univ., Columbus, OH (United States)
3. Univ. of California, Riverside, CA (United States)
4. National Institute for Materials Science (NIMS), Tsukuba (Japan)

Here, we study proximity-induced spin–orbit coupling (SOC) in bilayer graphene/few-layer WSe₂ heterostructure devices. Contact mode atomic force microscopy (AFM) cleaning yields ultraclean interfaces and high-mobility devices. In a perpendicular magnetic field, we measure the quantum Hall effect to determine the Landau level structure in the presence of out-of-plane Ising and in-plane Rashba SOC. A distinct Landau level crossing pattern emerges when tuning the charge density and displacement field independently with dual gates, originating from a layer-selective SOC proximity effect. Analyzing the Landau level crossings and measured inter-Landau level energy gaps yields the proximity-induced SOC energy scale. The Ising SOC is ~2.2 meV, 100 times higher than the intrinsic SOC in graphene, whereas its sign is consistent with theories predicting a dependence of SOC on interlayer twist angle. The Rashba SOC is ~15 meV. Finally, we infer the magnetic field dependence of the inter-Landau level Coulomb interactions. These ultraclean bilayer graphene/WSe₂ heterostructures provide a high mobility system with the potential to realize novel topological electronic states and manipulate spins in nanostructures.

• Research Organization: Univ. of California, Riverside, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0010597
• OSTI ID: 1802136
• Journal Information: Nano Letters, Journal Name: Nano Letters Journal Issue: 10 Vol. 19; ISSN 1530-6984
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
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