Gordillo, M.C.2014-06-162014-06-162008-07Physical Review Letters, 2008;101(4)0031-9007http://hdl.handle.net/10433/934The results of diffusion Monte Carlo calculations on the behavior of He4 adsorbed on the external surface of a bundle of carbon nanotubes are presented. The corrugation effects are found to be very important, making the outside part of the bundles a quite inhomogeneous substrate. No stable solid helium monolayer at high density was found. Instead, helium atoms are promoted to a second quasi-one-dimensional phase on top of the liquid first layer. On increasing the helium intake, a two layer structure is formed in which the helium directly in contact with the carbon surface solidifies.application/pdfenAmerican Physical SocietyMonte Carlo calculationsCarbon nanotubesjournal articleopen access