Buckling behavior of nanotubes from diamondene

Highlights: • The concept of a nanotube from diamondene is proposed. • The minimum radius for a stable armchair or zigzag DNT is predicted. • Under uni-axial compression, DNT has a critical buckling strain far greater than DWCNT with the same average diameter. • Buckling happens due to the breakage of C-C bonds in the outer layer of DNT. • In buckling, a damaged DNT has only one mode, but the undamaged CNTs have more modes. Under high pressure, two layers of graphene may have phase transition. After transition, a new two-dimensional material called as diamondene can be obtained, which recently has been verified by Raman spectra. As sp² & sp³ composites, diamondene possesses both excellent mechanical properties and semi-conductivity. Similar to the carbon nanotube (CNT) from tailored graphene, a nanotube can also be made from a diamondene ribbon. In this study, the mechanical stability of diamondene nanotubes (DNTs) is investigated by theoretical analysis after molecular dynamics calculations. Results demonstrate that the minimal radius of a DNT without broken bonds is far greater than that of a single-walled CNT. Comparing to the double-walled CNTs with the same length and average diameter, DNTs behave more stable under uniaxial compression. Before collapse due to breakage of sp³sp³ bond, a DNT has only one buckling mode. Under axial torsion, the wall of a DNT buckles at small torsion deformation. Between two edges of the nanotube, the shell becomes a warped ribbon at large torsion angle. During torsion, the number of broken bonds in the outer layer of DNT is far greater than that of the inner layer, and both numbers grow with the torsion angle. Few inter-layer bonds break due to the synchronous rotation of two layers in torsion.