Pressure effects on bilayer graphene (BLG)/WSe<sub>2</sub>/boron nitride (BN) device
ORAL
Abstract
Graphene/transition metal dichalcogenide (TMD) heterostructures combine the high mobility and gate tunability of graphene with strong spin-orbit coupling (SOC) and optical properties of 2D TMD. Clearly, in the 2D layered heterostructures, intimate contact is essential to proximity-induced phenomena such as WAL. In this study, WSe2 is transferred to exfoliated graphene on SiO2 by a pick-up technique and the graphene/WSe2 heterostructure is then protected by BN on top. We apply a hydrostatic pressure up to 2 GPa to the BLG (partially covered by WSe2)/WSe2/BN heterostructure and observe a clear insulating behavior in the WSe2-covered BLG region, indicating a band gap opening. This insulating behavior is enhanced as the pressure increases. However, in the uncovered BLG region, no clear insulating behavior is observed. In the meantime, we observe WAL in the WSe2-covered region, suggesting the strongly enhanced SOC in BLG via proximity effect. The charge neutral point of BLG consistently shifts from positive to slightly negative in the covered region with increasing pressure, which is another indicator that the coupling between BLG and WSe2 becomes stronger under high pressure.
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This work was supported by DOE BES Award No. DE-FG02-07ER46351 and NSF-ECCS and No. 1610447.
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Presenters
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Tang Su
- Peking University
- Physics, Univ of California - Riverside