Graphene-based heterostructures display a variety of phenomena that are strongly tunable by electrostatic local gates. Monolayer graphene (MLG) exhibits tunable surface plasmon polaritons, as revealed by scanning nano-infrared experiments. In bilayer graphene (BLG), an electronic gap is induced by a perpendicular displacement field. Gapped BLG is predicted to display unusual effects such as plasmon amplification and domain wall plasmons with significantly larger lifetime than MLG. Furthermore, a variety of correlated electronic phases highly sensitive to displacement fields have been observed in twisted graphene structures. However, applying perpendicular displacement fields in nano-infrared experiments has only recently become possible [Li, H.; et al. Nano Lett. 2020, 20, 3106-3112]. In this work, we fully characterize two approaches to realizing nano-optics compatible top gates: bilayer MoS2 and MLG. We perform nano-infrared imaging on both types of structures and evaluate their strengths and weaknesses. Our work paves the way for comprehensive near-field experiments of correlated phenomena and plasmonic effects in graphene-based heterostructures.
Bibliographical noteFunding Information:
Research in van der Waals heterostructures at Columbia was solely supported as part of Programmable Quantum Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award DE-SC0019443. D.N.B. is the Vannevar Bush Faculty Fellow (N00014-19-1-2630) and Moore Investigator in Quantum Materials EPIQS No. 9455. D.H. was supported by a fellowship from the Simons Foundation (579913). The work at Harvard was supported by NSF DMREF (Grant DMR-1922172). N.R.F. acknowledges support from the Stewardship Science Graduate Fellowship program provided under Cooperative Agreement No. DE-NA0003864. N.C. acknowledges the project SONAR, which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska–Curie Grant Agreement (No. 734690).
© 2021 American Chemical Society
- Bilayer graphene
- Nano-infrared imaging
- Top gate
PubMed: MeSH publication types
- Journal Article