First principles modeling of Mo6S9 nanowires via condensation of Mo4S6 clusters and the effect of iodine doping on structural and electronic properties

Abstract

By employing first principles DFT calculations, we propose a new stable model for Mo₆S₉ nanowires (NWs) obtained by condensing tetrahedral Mo₄S₆ clusters rather than octahedral Mo₆S₈ clusters, which are known as magic clusters in the Mo–S polyhedral cluster family. The pristine NW is found to be metallic and its local structure and physical properties can be tuned by doping of iodine atoms. This doping increases the number of Mo–Mo bonds in the NW, thus, Mo₄ tetrahedra are initially fused to the Mo₆ octahedron, and then, to the Mo₈ dodecahedron. Further, a close correlation among the Mo–Mo bonding in the local structure, mechanical and electronic properties, is observed from our study. Finally, the stability of the pristine and iodine doped Mo₈S_12−xI_x NW structures obtained from condensation of Mo₄ tetrahedra are found to be quite comparable with that of already reported Mo₆S_9−xI_x NWs with Mo₆ octahedra as building blocks.