The Study On Stress Regulation Of The Structure And Properties Of Borophene Heterostructure

Two-dimensional materials,due to their superior mechanical,thermal and electrical properties,have great application prospects in many fields,including nanoelectronic devices.Each two-dimensional material has its own unique performance characteristics,as well as its own disadvantages.In order to achieve complementary advantages,it is one of the commonly used methods to stack different materials to construct heterostructures.Such heterostructure constructed by van der Waals weak interaction opens up a new direction for the research of two-dimensional materials.With the rapid development of computing technology and the continuous upgrading of computing software and hardware,computational simulation is more and more widely used in the fields of physics,chemistry,life science and so on,and plays a more and more important role.In this paper,VASP software package was used to study the borophene-graphene heterostructure,and the following two aspects were studied:(1)Through first-principles-based density functional theory,the electronic properties of boronene-graphene heterostructure under different defect states are systematically studied.First,through the principle of lowest energy and molecular dynamics simulation,the ideal structure of the low-density defect state and the structure of the high-density defect state is screened.For single-atom vacancy defect,it is found that the nearest neighbor graphene side boron atom single-atom vacancy defect structure has the lowest energy,and show thermodynamic stability;on this basis,the double defects state structure was screened,and it was found that the neighboring graphene boron atom double vacancy defects is the most ideal structure when the adjacent arrangement is shown;the three atom vacancy defects has the best structure when the corner vacancy defects is shown.On the basis of the obtained defects structure,we have carried out a deeper understanding of the electronic properties of these structures.The study found that the complete heterostructure and the low-density defects state(including single-atom vacancy defect and diatomic vacancy defects)both exhibit metallic properties.High-density defect states(including three-atom vacancy defects)exhibit an indirect band gap semiconductor with 0.43 e V.(2)Based on the optimal structure,first-principles research methods are used to calculate the regulation and control effect of stress and strain on the electronic properties of the four structures.It is found that the non-defective and double-defective heterostructures are subjected to compression from 6% to 6%tension,and during this process,the structures exhibit metallic properties and fail to realize the transformation of electronic properties.For the single-defect structure,the tensile strain does not change the electronic characteristics,but when the compressive strain is 6%,the band gap opens,and the structure becomes an indirect band gap semiconductor with 0.1 e V.For the three defect structures,they all exhibit semiconductor characteristics during the process of stress and strain,but the band gap decreases to some extent.