Stability Analysis And Electronic Properties Of X₆Y₆(X=Mo,W;Y=S,Se,Te) Nanowires

Low-dimensional nanomaterials are one of the focuses of attention in the field of materials science and condensed matter physics nowadays.Compared with two-dimensional materials,one-dimensional materials have a more significant quantum confinement effect.Such feature also gives one-dimensional materials more prominent and excellent physical and chemical properties.As one typical one-dimensional nanostructure,transition metal chalcogenide nanowires are different from the semi-conductivity of layered 2H phase transition metal chalcogenide materials.Some transition metal chalcogenide nanowires are semi-conductivity and some are metallicity,and their electronic properties depend on their chalcogenide elements.Such behavior shows that we are expected to realize the electronic circuit of all transition metal chalcogenide nanowires.Exploring and studying such one-dimensional transition metal chalcogenide material can provide theoretical guidance for low-dimensional material design and device construction.Hence,this article mainly expands from the following two aspects:(1)By first-principles calculations,we systematically calculated the stability and electronic properties of transition metal chalcogenide nanowires(TMCNW)X₆Y₆(X=Mo,W;Y=S,Se,Te)encapsulated inside zigzag carbon nanotubes(CNT)with the diameter range of 10(?)?16(?).Our calculations show that due to the protection of CNTs,TMCNWs can often exist in some specific carbon tubes stably.In addition,we also found that despite the introduction of CNT,the initial electronic properties of TMCNW are still preserved.Finally,we discovered the phenomenon of charge transfer between CNT and TMCNW.By analyzing the charge transfer direction of the composite structures,we found that in the composite structure containing tellurium element,the charge is transferred from TMCNW to CNT;on the contrary,in the composite structure without tellurium,the charge is transferred from CNT to TMCNW.The results of this work reveal the stability and electronic properties of TMCNW in carbon nanotubes,and provide theoretical guidance for the further development of TMCNW in practical applications.(2)We applied the first principles to systematically explored the influence of Mo₆S₆ kink configuration on the electronic properties.Our calculations show that the kink structure of Mo₆S₆ with various lengths exhibits semi-conductivity different from that of the initial Mo₆S₆ nanowires,and the band gap values of Mo₆S₆ kink with different lengths are also different.Interestingly,the band gap predicted by band folding theory is extremely close to the calculated band gap.In addition,we also explored the effect of strain on the electronic properties of Mo₆S₆ kink structures.The results shows that the band gap value of the long kinks does not change greatly after applying different strains,indicating that the kinks have excellent electronic stability.We explained the electronic stability and changes of the Mo₆S₆ kink structures through the analysis of the change of the Mo-Mo bond length under the strain,and more research data shows such stability becomes more and more obvious with the length of the kinks.The findings of this work show that a certain band gap can be opened by kinking the metallic initial Mo₆S₆ nanowires,and promote the application prospects of the TMC nanowires in the field of micro devices.The electronic stability of Mo₆S₆ kinks under strain makes it to become one of the candidate materials for manufacturing flexible nanodevices.