Mechanical properties of diboron-porphyrin sheet under strain: A density functional theory study

The mechanical properties of a new two-dimensional semiconductor material named diboron-porphyrin (DP) are studied based on density functional theory. The behavior of DP monolayer under uniaxial and biaxial loadings as well as shear stress is investigated. The in-plane stiffness, Poisson's ratio, bulk and shear moduli of the DP monolayer are found to be close to those of a graphene sheet. It can be concluded that the DP monolayer has stiffness close to the graphene sheet. The difference in magnitude of in-plane stiffness and Poisson's ratio along x- and y-directions shows slightly anisotropic mechanical properties of DP monolayer. It is also observed that DP monolayers can bear high tensile strains before failure. The high stability and hardly deformable structure of DP monolayer are due to its high planar packing density which is comparable with graphene sheet. The fantastic mechanical properties of DP show these materials are desirable for application in nanomechanical devices.