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

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 Mo8S12-xIx NW structures obtained from condensation of Mo4 tetrahedra are found to be quite comparable with that of already reported Mo6S9-xIx NWs with Mo6 octahedra as building blocks.