Chiral vectors-tunable electronic property of MoS2 nanotubes

• The chirality plays a critical role in affecting the electronic property, wherein the armchair nanotube exhibits the indirect-band-gap and zigzag with direct-band-gap.
• The MoS2 NTs with lower chiral vectors occupy the relatively higher carrier mobility for both armchair and zigzag types.
• The similarity of lattice parameters and formation energy implies a potential possibility of transition between two types of NTs with low index chiral vectors.

It has been demonstrated that the mechanical and electronic properties of materials change significantly when the external dimension are confined to the nanoscale. Consequently, one-dimensional (1D) transition-metal dichalcogenide (TMDC) nanotubes (NTs), obtained from scrolling 2D TMDC, have attracted much attentions because of their intriguing properties and the chirality plays a key role in affecting the electronic properties. Taking the amount of speculations on the mechanism and the increasing needs for better device design and performance control, understanding the effect of chirality on the electronic properties is timely and relevant. Here, MoS2 NTs are comprehensively studied by first-principles calculations. The results show that the armchair (6≤ch≤14) exhibits the indirect-band-gap and zigzag (10≤ch≤20) with direct-band-gap. Moreover, the carrier mobility is enhanced with the decrease of radial length, in accord with the smaller effective mass of hole and electron for both types NTs. Finally, the formation energy showed that the smaller the radial diameters is, the harder the NTs is to form. Moreover, the similarity of lattice parameters and formation energy implies a potential possibility of transition between two types of NTs with low index chiral vectors, such as ANT(6,6)/ZNT(10,0).

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