| Black phosphorus is a typical two-dimensional semiconductor material in the post silicon era.As soon as it appears,it is very competitive in the nano electronic devices field because of its excellent electronic properties.Subsequently,due to the successful preparation of black phosphorus and its intrinsic negative Poisson ratio confirmed by experiments,black phosphorus has the possibility to extend the application of medical micro sensors and national defense equipment to nanoscale.The theoretical study shows that the negative Poisson’s ratio of black phosphorus comes from its unique puckered structure.Because of the structure of two-dimensional semiconductor materials(including monolayer W-Sb,aW-Sb,SiS,SiSe and SnTe)similar to black phosphorus,the mechanical properties of them,especially Poisson’s ratio,are worth studying.In this paper,the mechanical properties of the above two-dimensional puckered materials are systematically calculated by using the first principle calculation.The results show that monolayer SiS,SiSe,SnTe and W-Sb have negative out of plane Poisson’s ratio,while aW-Sb does not.Especially,monolayer SiSe has large NPR under uniaxial strain in both the x direction(Vzx=-0.466)and y direction(vzy=-0.413).which are 15 times that of monolayer black phosphorus(vzy=-0.027).This large negative Poisson material is expected to improve the sensitivity of microsensors and the protective performance of defense equipment.By applying uniaxial stress to the puckered structure,the phase structure of monolayer SiSe and SnTe and the symbol of their Poisson’s ratio can be changed,which is a feasible way to design adjustable negative Poisson’s ratio materials.On the basis of this study,and referring to the previous literature on two-dimensional puckered materials,a deformation mechanism of intrinsic negative Poisson’s ratio suitable for puckered structures(including monolayer BP,As,Sb,SiS,SiSe,GeS,GeSe,SnS,SnSe and SnTe)is provided.Our work sheds light on the mechanical properties of the 2D materials with the puckered structures. |
