Improved Dreiding force field for single layer black phosphorus.

We present an improved Dreiding force field for single layer black phosphorus (SLBP) obtained by first-principle calculations in conjunction with the particle swarm optimization algorithm and molecular dynamics (MD) simulations. The proposed Dreiding force field can describe material properties of the SLBP very well in comparison with first-principle calculations and the Stillinger-Weber potential, including Young's modulus, Poisson's ratio, shear modulus, bending stiffness and phonon spectrum. Through the improved Dreiding force field, the wetting of a water nanodroplet and the adsorption of a villin headpiece on SLBP under compressive deformation are also studied by MD simulations. The simulation results show that the microscopic contact angle increases with the level of compressive strain on the SLBP. Meanwhile, the compressive strain reduces disruption caused by SLBP to the structure of the villin headpiece. The proposed Dreiding force field shows great potential to describe the interaction between SLBP and water molecules. It can be further used to simulate the transport of water on SLBP, especially under mechanical deformation, and interactions between SLBP and biological systems.