Quantum effects in the radial thermal expansion of bundles of single-walled carbon nanotubes doped with 4He
A.V. Dolbin, V.B. Esel'son, V.G. Gavrilko, V.G. Manzhelii, N.A. Vinnikov, and S.N. Popov
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
Department of Physics, Umea University, SE - 901 87 Umea, Sweden
Received 26 March, 2010
The radial thermal expansion αr of bundles of single-walled carbon nanotubes saturated with 4He impurities to the molar concentration 9.4% has been investigated in the interval 2.5–9.5 K using the dilatometric method. In the interval 2.1–3.7 K αr is negative and is several times higher than the negative αr for pure nanotube bundles. This most likely points to 4He atom tunneling between different positions in the nanotube bundle system. The
excess expansion was reduced with decreasing 4He concentration.
PACS: 65.80.–g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems.