Investigation on electronic properties of functionalized arsenene nanoribbon and nanotubes: A first-principles study

Chiraltube, rolling 2D materials into chiral nanotubes

Carbon nanotubes (NTs) are graphene sheets rolled into a 1D material, with a specific chirality that defines its structure and properties. Graphene has triggered the development of thousands of 2D materials, which in principle could also be rolled into 1D NTs. However, most of these NTs have not been proposed due to difficulties in the generation of atomic coordinates for chiral NTs from 2D materials with a non-hexagonal lattice or multi-layered materials. In this paper we present Chiraltube, an open-source Python code that allows the quick generation of a complete NT with any chirality from the unit cell of its original 2D material. We explain the inner workings of the code as well as the theoretical background on which it is built, generalizing concepts from the construction of chiral and achiral carbon NTs to work on any other 2D material. We show various examples of the resulting chiral NT structures built from phosphorene, MoS2 and Ti3C2, and present some analysis on the interatomic distortion in the outermost layers of these NTs, as well as the results of ab initio electronic structure calculations on a set of phosphorene NTs generated by the program, showing the immediate practicality and usefulness of the program. We also explore some limitations and details of the tool as well as further work to be done.

The effects of vacancy and heteroatoms-doping on the stability, electronic and magnetic properties of blue phosphorene

In this work, we have systematically studied the stability, electronic structure and magnetic properties of the pristine, four defect states case of blue phosphorene and the six heteroatoms doping in blue phosphorene by first-principles calculations. In our findings, both defects and heteroatoms doping can regulate the band gap of blue phosphorene and the transition from indirect to direct band gap can be dramatically tuned by DV1BP, DV2BP and Al, Si atoms substitutional doping in blue phosphorene. The presence of defects and heteroatoms doping effectively modulates the electronic properties of blue phosphorene, rendering the defect-containing phosphorene semiconducting with a tunable band gap. Spin-orbit coupling can be induced by introducing SV-, DV- defects in blue phosphorene. The results provide theoretical guidance for future bandgap regulation and magnetism, defective and substitutional doping blue phosphorene may have potential electro-optical and electromagnetic applications.

Investigation of the mechanism of overall water splitting in UV-visible and infrared regions with SnC/arsenene vdW heterostructures in different configurations

Monolayer arsenene presents good stability and high photogenic carrier mobility. However, a high photogenic electron and hole pair recombination rate seriously reduces its photocatalytic activity. The photocatalytic activity can be effectively improved by building type II heterostructures. In this work, SnC/arsenene heterostructures in three configurations are studied using first-principles calculations. Their structure, stability, and electronic and photocatalytic properties are investigated. It is found that all SnC/arsenene heterostructures are stable, and form type-II band edges, which effectively promote the transfer of photogenerated electrons from the SnC monolayer to the arsenene sheet. The charge transfer between SnC and arsenene leads to a built-in electric field in the interface region, which is favorable for inhibiting photogenic electron and hole pair recombination. Compared with the monolayer arsenene, the photocatalytic activity is greatly improved and the absorption spectrum of SnC/arsenene heterostructures is expanded. Attractively, these three heterostructures present two different photocatalytic mechanisms. H1 and H3 configurations were taken as examples to study their photocatalytic properties for overall water splitting at varying pH values and external strains. We found that alkaline conditions were more favorable for photocatalysis of SnC/arsenene heterostructures. In particular, H3 can still achieve full photocatalytic water decomposition in the near infrared region. These results show that the SnC/arsenene heterostructures are a prospective material for photocatalysis application.