DFT Study of Aln (1−13) Clusters Encapsulated Inside Single Walled Carbon Nanotubes

Abstract

We have carried out a systematic investigation of encapsulation of Aln clusters for n = 1−13 inside armchair single walled carbon nanotubes (SWCNTs)(m,m) of varying diameter using density functional theory calculations. The effect of confinement was studied on the Aln geometries which shows linear structures for n ≤ 5 in SWCNTS (m,m) [m 5 and m > 6. In strong confinement, Al−C interaction becomes more dominant and if we relax the effect of confinement, then the Al−Al interactions become relatively more important. It was observed that the clusters have a tendency to form nanowires in strong confinement and retain their free space geometries in less confinement. The HOMO−LUMO gap of the hybrid structures Aln@(6, 6) for n = 1−13 decreases to 0.10−0.20 eV w.r.t pure SWCNTs. In Aln@(8,8), the HOMO−LUMO gap shows an oscillatory odd−even pattern, with higher values for odd n (n > 5) and a maximum value of 1.11 eV for n = 7. The Mulliken charge analysis on Aln@SWCNT, show...