Structural and electronic properties of Mo₆S₃I₆ nanowires by newly proposed theoretical compositional ordering

The structural, electronic, and magnetic properties of molybdenum-based nanowires have been actively investigated for their potential applications in nanodevices; however, further advancement is hindered by incomplete knowledge of the electronic and atomic structures of Mo₆S₃I₆. To facilitate further development of Mo₆S₃I₆ nanowire devices, we propose possible atomic structures and corresponding electronic properties of Mo₆S₃I₆ nanowires based on density functional theory. We explored various combinations of atomic structures by changing the positions of sulfur and iodine atoms linked to the two Mo₆ octahedra in the Mo₆S₃I₆ unit cell. We found two stable local energy minima structures characterized by elongation of the wire length, and therefore propose 28 possible atomic configurations. We calculated band structures of the newly proposed atomic models and found three structures that behaved as conductors. According to our compositional ordering structural analysis, we concluded that (i) periodic distortion of the bond lengths influences the behavior of the electrons in the system, (ii) the role of sulfur atoms in the bridging plane is important for intramolecular charge transport due to delocalized charge differences, and (iii) the electronic band gap energy is proportional to the integrated Mo-S bonding orbital energy.