Monte Carlo simulation of intercalated carbon nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Carbon nanotubes (CNTs) are widely studied for their unique properties.
• Intercalation of metals into CNTs offers potential for novel composite materials.
• Understanding metal-CNT interactions is crucial for designing advanced nanostructures.

Purpose of the Study:

• To investigate the intercalation of iron (Fe) and cobalt (Co) atoms within single- and double-walled carbon nanotubes (CNTs).
• To establish the relationship between CNT length, metal atom type, and their quantity.
• To determine factors influencing the stability of these metal-intercalated CNT systems.

Main Methods:

• Monte Carlo simulations were employed to model the systems.
• The Tersoff potential was utilized to describe interatomic interactions.
• Simulations analyzed the behavior of Fe and Co atoms within CNTs of varying lengths and structures.

Main Results:

• A correlation was found between CNT length and the number of intercalated metal atoms.
• For a (9,0) CNT of 3.60 nm length, more than eight Fe atoms led to extrusion, unlike Co atoms.
• Systems are stabilized by 3d-atom coordination near the CNT wall (0.18-0.20 nm radius-vector).
• Smaller systems showed ground-state stabilization between 400-700 K, unlike larger ones.
• Van der Waals interactions influenced Co atom behavior in double-walled CNTs differently than Fe atoms.

Conclusions:

• The maximum number of Fe atoms that can be intercalated into a specific CNT size is limited (e.g., eight Fe atoms for a 3.60 nm (9,0) CNT).
• Temperature plays a role in the stabilization of smaller intercalated systems.
• The interaction dynamics of Fe and Co atoms within double-walled CNTs differ due to interatomic forces.