Quasi one dimensional ${}^4$He inside carbon nanotubes

Abstract

We report results of diffusion Monte Carlo calculations for both ${}^4$He absorbed in a narrow single walled carbon nanotube (R = 3.42 Å) and strictly one dimensional ${}^4$He. Inside the tube, the binding energy of liquid ${}^4$He is approximately three times larger than on planar graphite. At low linear densities, ${}^4$He in a nanotube is an experimental realization of a one-dimensional quantum fluid. However, when the density increases the structural and energetic properties of both systems differ. At high density, a quasi-continuous liquid-solid phase transition is observed in both cases.

11 pages, 3ps figures, to appear in Phys. Rev. B (RC)