RESUMEN
The stretching and compression effects on puckered arsenene nanotubes (AsNTs) are investigated by using density functional calculations. The atomic arrangement determines the nanotube properties and relative stability; therefore, zigzag, chiral, and armchair present different properties. Since the AsNT properties depend on the diameter, three cases are considered: (a) (0, 9) and (9, 0), (b) (0, 14) and (14, 0), and (c) (0, 19) and (19, 0) NTs. For all calculated parameters of the smallest NTs, it is found that the armchair (0, 9) nanotube is always more stable than the zigzag (9, 0) nanotube. On the other hand, for the two largest NTs, a structural transition from armchair to zigzag is found upon stretching. Phase transitions are of great interest, in part because they result in changes of the properties of the material under study, changes that can be used in many technologies. To our knowledge, this is the first time that a structural transition in a puckered nanotube has been predicted. Our results show that the electronic band gap of the AsNTs can be modulated by increasing or decreasing the axial lattice parameter. It is also found that semiconductor NTs are more stable than metallic NTs.
RESUMEN
The structure of penta-graphene (penta-C), an irregular pentagonal two-dimensional (2D) structure, has been predicted recently. In this communication we carried out a dispersion-corrected density functional theory (DFT-D) study of the penta-C doped with Si, Ge and Sn atoms and its related hydrogenated penta-C structures (H-penta-C-X). We predict various new structures as thermally stable based on Born-Oppenheimer molecular dynamics (BOMD) calculations. Moreover, their dynamical stability is attested by phonon dispersions spectra. In general, we found that the bandgap value of doped structures reduces, while H-penta-C-X show large bandgap values. This feature can be exploited for potential uses of hydrogenated doped-penta-C structures as dielectric layers in electronic devices.
RESUMEN
The study of black phosphorus nanotubes (PNTs) had been devoted to zigzag and armchair structures, with no consideration of chiral structures to date. In this communication, we studied the structural and electronic (band structure) properties of chiral nanotubes using a periodic plane wave-pseudopotential approach. We found that some chiral nanotubes display similar bandgaps and binding energies per atom (BEA) as armchair PNTs and Born-Oppenheimer molecular dynamics (BOMD) calculations attest their thermal stability. Interestingly, we determined that the bandgap is tuned by varying the PNTs chirality and it is not related to their diameters. This feature can be exploited in optical and electronic applications wherein a direct and sizable bandgap is required.