Séminaire

Vendredi 17 Juin 2022 à 11h00.

Double-walled carbon nanotube: A unique model system for studying coupling at the nanoscale

''Using an experimental approach that combines high-resolution electron microscopy, electron diffraction and optical spectroscopies, including Raman scattering, spatial modulation spectroscopy (optical absorption), Rayleigh spectroscopy and photoluminescence, on individual, spatially isolated and suspended (free-standing) single-walled (SWNTs) and double-walled carbon nanotubes (DWNTs), we have been able to investigate their phonons characteristics, electronic and optical properties. In this talk, we present an overview of the most significant results obtained via this approach. Particular attention is paid to the study of DWNTs, coaxial composites of two SWNTs, which provide a unique model system for studying coupling at the nanoscale. We show how such coupling, originating from the van der Waals interaction between the inner and outer nanotubes, plays a crucial role in determining the characteristics of the collective radial breathing-like modes and G modes in DWNTs (for a review see Ref. 1-2). We will also discuss how the photoluminescence of inner semiconducting tubes is affected by the presence of the outer tubes.[3] Finally, the observation of an optically active cross-band transition in DWNT absent in its constituting SWNTs will be reported.[4]

References:
1. T. Michel et al. in “Optical properties of carbon nanotubes: a volume dedicated to the memory of Mildred Dresselhaus”, Handbook of Carbon Nanomaterials, Vol. 10, ISBN: 978-981-3235-45-8 (2019) and references therein.
2 .D. Levshov et al. , Carbon 114, 141 (2017) and references therein.
3. D. Levshov et al. , Phys. Rev. B 96 (19), 195410 (2017).
4. M. Paillet et al., Carbon 196, 950 (2021).
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