New physical insight in structural and electronic properties of InSb nano-sheet being rolled up into single-wall nanotubes

Abstract

The structure evolution and the electronic properties of InSb monolayers and nanotubes were thoroughly studied by first-principles theory. The results showed that InSb monolayer exhibits intrinsic electric polarization of 12 pC/m, and the direction of electric polarization can be switched when strain or external electric fields are applied. InSb monolayer has a high electron and hole-mobility of ~7 × 103 and 0.7 × 102, respectively. When the monolayer is rolled up to form nanotubes, the optimized parameters, energy level, and electronic structure, were calculated for the armchair and the zigzag configurations. The calculated electronic structure shows that the monolayer has a direct band gap of 1.29 eV, while after being rolled up into small diameter InSb [6] and InSb (6,0) nanotubes, there is an increase of the band gap to 1.58 and 1.70 eV for the two aforementioned configurations, respectively. Furthermore, the strain energy of the nanotubes is lower than that of the monolayer. The increase of band gap when the monolayer was rolled up into nanotubes was attributed to p-p coupling between In-3p orbital in the conduction band of InSb in nanotubes. The findings of the present work suggest that InSb monolayer may have observable ferroelectricity; thus, it can qualify for consideration in information storage applications.