Regensburg 2025 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 63: Focus Session: Nanoscale Light-matter Interaction II

HL 63.1: Vortrag

Freitag, 21. März 2025, 12:00–12:15, H14

Super-resolution imaging of nanoscale inhomogeneities in hBN-covered and encapsulated few-layer graphene — •Lina Jäckering, Konstantin G. Wirth, Lukas Conrads, and Thomas Taubner — I. Institute of Physics (IA), RWTH Aachen University

Encapsulating few-layer graphene (FLG) in hexagonal boron nitride (hBN) can cause nanoscale inhomogeneities in the FLG, including changes in stacking domains and topographic defects.[1] Due to the diffraction limit, characterizing these inhomogeneities is challenging. Recently, the visualization of stacking domains in encapsulated four-layer graphene (4LG) has been demonstrated with phonon polariton (PhP)-assisted near-field imaging.[2] However, the underlying coupling mechanism and ability to image subdiffractional-sized inhomogeneities remain unknown. Here, we retrieve direct replicas and magnified images of subdiffractional-sized inhomogeneities in hBN-covered trilayer graphene (TLG) and encapsulated 4LG, enabled by the hyperlensing effect.[3] This hyperlensing effect is mediated by hBN*s hyperbolic PhP that couple to the FLG*s plasmon polaritons. Using near-field microscopy, we identify the coupling by determining the polariton dispersion in hBN-covered TLG to be stacking-dependent. Our work demonstrates super-resolution and magnified imaging of inhomogeneities, paving the way for the realization of homogeneous encapsulated FLG transport samples to study correlated physics.

[1] Geisenhof et al. ACS Appl. Nano Mater. 2, 6067 (2019). [2] Liu et al. Nat. nanotech. 19, 188-195 (2024). [3] Li et al. Nat. Commun. 6, 7507 (2015).

Keywords: graphene; hBN; defect imaging; hyperlensing; s-SNOM