A one-dimensional Ising model for C70 molecular ordering in C70-peapods

Abstract

Adescription using the Ising model is proposed for the C70 molecular orientational ordering in C70 one-dimensional crystals formed inside single-wall carbon nanotubes (SWNTs). It is shown that the observed standing and lying alignments can be deduced naturally from the present Ising model where the SWNT diameter effectively changes the 'effective field' acting on C70 molecules. The thermal expansion of the C70 intermolecular distance is well described by this model. The possibility of antiferro-orientational ordering is also suggested.