Keywords :
carbon nanotubes; dielectric screening; double-walled nanotubes; excitons; one-dimensional heterostructures; resonant Raman; Inner tubes; Many-body effect; Metallics; Nano scale; One-dimensional; One-dimensional heterostructure; Optical technique; Bioengineering; Chemistry (all); Materials Science (all); Condensed Matter Physics; Mechanical Engineering; one-dimensionalheterostructures; resonantRaman
Abstract :
[en] Dielectric screening plays a vital role in determining physical properties at the nanoscale and affects our ability to detect and characterize nanomaterials using optical techniques. We study how dielectric screening changes electromagnetic fields and many-body effects in nanostructures encapsulated inside carbon nanotubes. First, we show that metallic outer walls reduce the scattering intensity of the inner tube by 2 orders of magnitude compared to that of air-suspended inner tubes, in line with our local field calculations. Second, we find that the dielectric shift of the optical transition energies in the inner walls is greater when the outer tube is metallic than when it is semiconducting. The magnitude of the shift suggests that the excitons in small-diameter inner metallic tubes are thermally dissociated at room temperature if the outer tube is also metallic, and in essence, we observe band-to-band transitions in thin metallic double-walled nanotubes.
Funding text :
G.G. and S.R. acknowledge the Focus Area NanoScale of Freie Universitaet Berlin and the supraFAB Research Center. S.R. acknowledges support by the Deutsche Forschungsgemeinschaft under Grant SPP 2244 (443275027) and the European Research Council ERC under Grant DarkSERS (772108). B.S.F. acknowledges support from the DFG under Grants FL 834/5-1, FL 834/7-1, FL 834/12-1, FL834/13-1, and FL 834/9-1. G.G. acknowledges funding from the Luxembourg National Research Fund (FNR) under Project [AWORD].
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