Computer simulation of conductive linear sulfur chains confined in carbon nanotubes

CK Addington and JM Mansell and KE Gubbins, MOLECULAR SIMULATION, 43, 519-525 (2017).

DOI: 10.1080/08927022.2016.1269259

Recent experimental studies have shown that when sulfur is confined within a carbon nanotube (CNT) of appropriate diameter it forms a covalently bonded linear chain, and this confined one-dimensional sulfur phase is metallic. Such one-dimensional phases of sulfur are not observed in the bulk material, but at pressures in excess of 83GPa bulk sulfur does form a metallic monoclinic phase. This suggests that the 1-D conducting phase formed in confinement may arise from high pressures arising due to the strong confinement. Here we report atomistic molecular dynamics of sulfur within (8,0) CNTs, using a recently derived statistical method for calculations of the pressure tensor, we find axial pressure component values as high as 8 x 10(6) bar (800 GPa) for the SWLJ case. We decompose the pressure into contributions from sulfur- sulfur (S-S) and sulfur-carbon (S-C) interactions, and find that S-S interactions are strongly attractive, while S-C interactions are strongly repulsive.

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