Study On The Regulation Method Of Phosphorene Mechanical Properties Based On Molecular Dynamics Simulation

In 2004,the successful preparation of graphene led to the research upsurge of two-dimensional materials.Two dimensional materials are thin films with the scale of single atomic layer,which means the size of nano scale.The quantum confinement effect caused by this unique size has many interesting properties,which has attracted people's attention.Graphene,molybdenum disulfide and black phosphorus all belong to two-dimensional material family.Compared with graphene and molybdenum disulfide,black phosphorus has both direct band gap and high carrier mobility,which makes it an ideal material for semiconductor devices and optoelectronic devices,as well as a broad application prospect.However,at present,the research on black phosphorus mainly focuses on the electrical,magnetic,optical and other properties.As for the mechanical properties of black phosphorus there is a certain gap.The understanding of black phosphorus mechanics is the basis of its various applications,so it is of theoretical guidance and practical significance to study the mechanical control methods of black phosphorus.Phosphorene is a single layer of black phosphorus.Because of its small size and difficult preparation,the existing equipment and instruments for physical research is expensive.However,the existing theory is still blank for two-dimensional materials.At this time,using the computer simulation research method,not only can obtain the macroscopic conclusion like the experiment,but also can reduce the cost of the experiment.In this paper,the molecular dynamics simulation method is used to explore the control means of the mechanical properties of double-layer phosphorene.The main research variables include temperature,angle between layers and doping.Through the modeling under different research variables to control the variables,the stress-strain curve of the model is obtained by the simulation experiment of uniaxial tension,and then the mechanical properties are derived by analyzing the characteristics of the curve.In this paper,we mainly focus on the mechanical properties,including the critical strain and stress,anisotropy and Young's modulus.The results show that the increase of temperature will lead to the decrease of critical strain,critical stress and anisotropy(36%in zigzag direction and 44%in armchair,22%in armchair and 42%in armchair,respectively),but it will lead to the increase of Young's modulus;the influence of rotation angle is more complex,which can increase the regulation range of phosphorene,make the regulation of phosphorene more flexible,and the 90 degree rotation angle will cause the dropping of anisotropy.5%Fe doping will lead to the decrease of critical strain,critical stress(45%in zigzag direction and 58%in armchair,74%in armchair and 72%in armchair)and anisotropy of phosphorene.At a certain concentration threshold,Young's modulus will decrease,but the decrease value does not increase with the further increase of concentration and maintains a stable value.In addition,dopant can make phosphorene produce a property that the critical stress will not drop sharply after reaching the critical strain.Through comparative analysis,it can be found that it is not ideal to comprehensively improve the mechanical properties of the phosphorene materials,but the other part can be improved at the expense of one part of the performance by means of regulation and control.The results of this paper are helpful for the further application of phosphorene.