Investigation on electronic and mechanical properties of penta-graphene nanotubes

Abstract

Penta-graphene nanotubes (PGNTs), a type of novel one-dimensional materials, express excellent electronic, thermal and mechanical properties with great potential for inspiring unconventional optoelectronic devices design. In this work, electronic properties and mechanical behaviors of PGNTs under axial tension and compression loadings were investigated using density functional theory and molecular dynamics method. Several models of PGNTs were constructed to highlight important insights about band structure, charge population, atom orbital and fracture behavior. It is found that the band gap decreases relatively as the size increases. The band gap in (9,9) PGNT decreases with the compressive strain, while it increases with the tensile strain. Charge transformation can be found with the strain variation and observed using the HOMO–LUMO orbitals. The mechanical parameters are fluctuated with the PGNTs diameter. During the fracture process of (9,9) PGNT, the C1–C1 and C1–C2 bonds act as the main stress-bearing bonds. With the continuous tensile strain increase, an eight-member ring forms at the critical state and acts as a defect. The breaking of bonds occurs then around this newly born defect, which leads to the final fracture of the tube. The results of this investigation bring a better understanding of the PGNTs intrinsic properties.