Fe4 cluster adsorbed on single-wall carbon nanotubes: A density functional study

First-principles computational methods were performed to investigate the structure, total energy and electronic properties of Fe4 cluster adsorbed on metallic (5, 5), (6, 6) and semiconducting (8, 0) single-wall carbon nanotubes (SWNTs). In Fe4 + SWNT system, the equilibrium structure of adsorbed Fe4 cluster is affected by two competitive effects: Fe–C and Fe–Fe interactions. It was found that the tetrahedral structure was the most stable configuration in all cases. Comparing to the free cluster, the magnetic moment of the adsorbed Fe4 cluster decreases by Fe–C interaction, but still keeps larger magnetic moments than bulk iron, so the whole compound presents high spin-polarized. Our study suggests a possible architecture of metal clusters absorbed on carbon nanotubes and its analogues, which can be further exploited for the design of nanoscale magnets, nanotube-based catalyzer and nanoelectronic devices.