Exploring 2D Materials with Synchrotron Infrared-to-Terahertz Nanospectroscopy

ORAL

Abstract

Many fundamental excitations of 2D materials have resonance energies of a few 10 to 100 meV, i.e., in the infrared and terahertz (THz) frequency range. Infrared nanospectroscopy provides direct access to these excitations with a spatial resolution of ~10 nm. At the National Synchrotron Light Source II (NSLS-II), we established a new nanospectroscopy setup, which uniquely covers the ultrabroad frequency range from 5-242 THz (175-8000 cm‑1, 22-1000 meV). We highlight various results obtained with this setup, such as terahertz polariton interferometry of the van der Waals material GeS [1], graphene cavity plasmonics [2], and negative polaritonic refraction in an hBN-MoO3 hetero-bicrystal [3]. Also, we will discuss the novel opportunities of performing infrared nanospectroscopy in high magnetic fields (≤7 T) [4,5].



The infrared nanospectroscopy setup at the 22IR2/MET beamline of NSLS-II is available for general use. Application for beamtime: https://www.bnl.gov/nsls2/userguide/



[1] L. Wehmeier et al., ACS Photonics 10, 4329 (2023).

[2] R. A. Vitalone et al., ACS Nano (2024).

[3] L. Wehmeier, S.-J. Yu et al., Adv. Mater. 36, 2401349 (2024).

[4] M. Dapolito et al., Nat. Nanotechnol. 18, 1409 (2023).

[5] L. Wehmeier et al., Sci. Adv. 10, eadp3487 (2024).

*We thank Attocube for the use of the NeaSNOM near-field microscope. Research on near-field studies of low dimensional materials is supported as part of Programmable Quantum Materials (Pro-QM), an Energy Frontier Research Center (EFRC) funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under award DE-SC0019443. The construction of the near-field instrument was funded by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Co-design Center for Quantum Advantage (C2QA) under contract number DE-SC0012704. This research used the 22IR2/MET beamline of the National Synchrotron Light Source II and Quantum Material Press (QPress) of the Center for Functional Nanomaterials (CFN), which are U.S. Department of Energy Office of Science User Facilities at Brookhaven National Laboratory under Contract No. DE-SC0012704.

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Presenters

  • Lukas Wehmeier

    • Brookhaven National Laboratory (BNL)

Authors

  • Lukas Wehmeier

    • Brookhaven National Laboratory (BNL)

  • Mengkun Liu

    • Stony Brook University (SUNY)

  • Steven L Hulbert

    • Brookhaven National Laboratory (BNL)

  • Christopher C Homes

    • Brookhaven National Laboratory (BNL)

  • Dmitri N Basov

    • Columbia University

  • G.Lawrence Carr

    • Brookhaven National Laboratory