Structural Stability And Electronic Properties Of Arsenene Nanotubes:A First Principle Study

Since we found a lot of two dimensional nanomaterials, such as graphene, BN,transition metal dichalcogenides(TMDCs). Due to their special topological structure,and favourable mechanical and electrical properties, they are paid more extensively attentions, and used in material, medicine and other fields. In 2014, a new two dimensional material, the phosphorene have been fabricated in experiment, and then the arsenene are predicted in theory. They all belong to the group-V element, and have five electronics in the outer layer. The atoms are bonded in the way of sp3 hybridization,and they may have many different allotropes. It is reported that the phosphorene has many different allotropes, such as black phosphorene, blue phosphorene and so on. Arsenene also has two allotropes, the black-P like and blue-P like structures. Arsenene has a strong chemical stability, excellent mechanical and electrical performance. In the past, people hope that curving the two-dimensional crystal into a new nanotube structure, and the new one dimensional nanotube structures have better physical properties than two dimensional structures. They can be widely used in all walks in life. Therefore, considering the arsenene is a new type of two dimensional structure, we can curve the arsenene nanosheet into the arsenene nanotube in the way of carbon nanotube-like.Then, we predicts the arsenene nanotube structures in theory.We adopted the first principles method based on density functional theory,relying on the VASP and CP2 K packages, to study the new one dimensional structure,the arsenene nanotube. Firstly, we executed some computing simulations for the arsenene nanotube structures. Then, we could get the possible subsistent structure of arsenic nanotubes, and analyzed the structure information of nanotubes with different diameter size. According to the stable structures, we studied their electronic properties and dynamical stability. The results show that arsenene nanotubes is a semiconductor with a large band gap, the band gap is about 1.6eV in common. The armchair nanotubes is a semiconductor with direct band gap, and zigzag nanotubes is a semiconductor with indirect band gap. If the radius of nanotubes is less than 5.5 ?,the band gap increases with the increase of the radius. If the radius is greater than5.5?, the band gap decreases with the increase of the radius gradually, and tends to the value of the band gap of the arsenene. We applied expansion or compression for the nanotubes,and found that the strain can cause great impact on the band gap, if weimpose strain about-9%~9%, the band gap decreases form 1.6eV to 0.2eV, and a transition between direct and indirect band gap will happen. We also use the Ab Initio Molecular Dynamic method to executed molecular dynamics simulations for the nanotubes. After the simulations for the nanotubes with different radius in different temperature, we found that the nanotubes with a more than 4.0? radius can exist and keep stable at the room temperature,or in higher temperature condition(800K).