SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 93: Graphene II: Electronic Structure and Growth
O 93.3: Vortrag
Freitag, 31. März 2023, 11:00–11:15, GER 37
Near-field optical investigation of tetralayer graphene reveals ABCB stacking — •Konstantin G. Wirth1, Jonas B. Hauck2, Alexander Rothstein3, Christoph Stampfer3, Dante M. Kennes2, Lutz Waldecker3, and Thomas Taubner1 — 1I. Institute of Physics (IA), RWTH Aachen University — 2Institute for Theory of Statistical Physics, RWTH Aachen University — 32nd Institute of Physics, RWTH Aachen University
The crystallographic structure of few-layer graphene (FLG) greatly influences its electronic and optical properties. Local probing of the stacking order is usually done by optical measurements, such as infrared absorption [1] or Raman spectroscopy, which work for non-contacted and encapsulated samples but are limited in lateral resolution by diffraction to a few micrometer. Here, we directly probe the electronic properties of tetralayer graphene (4LG) with amplitude and phase-resolved near-field spectroscopy with a broadly tunable laser source over the energy range from 0.28 to 0.56 eV. We differentiate between rhombohedral and Bernal stacking sequences and reveal domains of the previously elusive third stacking order of 4LG, namely ABCB[2], by addressing distinctive interband contributions in optical conductivity. These results establish near-field spectroscopy at the interband transitions as a semi-quantitative tool, enabling the recognition and characterization of FLG domains.
[1] Mak et al., PNAS, 2010 107, 14999-15004 [2] Wirth et al., ACS Nano 2022, 16, 16617-16623