Low frequency excitations of C60 chains inserted inside single-walled carbon nanotubes

Julien Cambedouzou (1) , Stéphane Rols (1) , Robert Almairac (1) , Jean-Louis Sauvajol (1) , Hiromichi Kataura (2) , Helmut Schober (3)

1 GDPC - Groupe de Dynamique des Phases Condensées
2 NRI - Nanotechnology Research Institute
3 ILL - Institut Laue-Langevin

The low frequency excitations of C60 chains inserted inside single-walled carbon nanotubes (SWNTs) have been studied by inelastic neutron scattering (INS) on a high quality sample of peapods. The comparison of the neutron-derived generalized phonon density of states (GDOS) of the peapods sample with that of a raw SWNTs allows the vibrational properties of the C60 chains encapsulated in the hollow core of the SWNTs to be probed. Lattice dynamical models are used to calculate the GDOS of chains of monomers, dimers and polymers inserted into SWNTs, which are compared to the experimental data. The presence of strong interactions between C60 cages inside the nanotube is clearly demonstrated by an excess of mode density in the frequency range around 10 meV. However, the presence of a quasi-elastic signal indicates that some of the C60\'s undergo rotational motion. This suggests that peapods are made from a mixture of C60 monomers and C60 n-mer (dimer, trimer ... polymer) structures.

Mots clés: carbon nanotubes; C60; peapods; inelastic neutron scattering; diffraction

Domaines: Autre [cond-mat.other]

Julien Cambedouzou, Stéphane Rols, Robert Almairac, Jean-Louis Sauvajol, Hiromichi Kataura, et al.. Low frequency excitations of C60 chains inserted inside single-walled carbon nanotubes. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2005, 71, pp.041403(R). ⟨10.1103/PhysRevB.71.041403⟩. ⟨hal-00004222⟩