Development of a second-nearest-neighbor modified embedded atom method potential for silicon-phosphorus binary system

B Liu and H Zhang and JY Tao and ZR Liu and X Chen and YA Zhang, COMPUTATIONAL MATERIALS SCIENCE, 120, 1-12 (2016).

DOI: 10.1016/j.commatsci.2016.04.002

Phosphorus (P) is one of the most common impurities in silicon (Si). To investigate the effects of P on the mechanical properties of Si at nano or atomic scale, the second-nearest-neighbor Modified Embedded Atom Method model (2NN MEAM) potentials for pure P and Si-P binary system are developed using genetic algorithm (GA). The reference physical properties for the parameterization for pure P include cohesive energies, lattice constants, bulk moduli and first order pressure derivatives of experimentally-existing phases. The van der Waals interactions in P are not considered since it's beyond the description of MEAM and it's less important in covalently bonded Si-P compounds. For Si-P binary system, cohesive or formation energies, lattice constants and elastic constants of typical Si-P structures, properties of point defects and P-vacancy pairs are considered. The robustness of the newly developed potentials is examined by testing the thermal stability and transformation from non-equilibrium to ordered phase. The effects of P on the tensile behaviors of bulk Si are demonstrated. Results show that phosphorus lowers the fracture threshold and stiffness of bulk Si. (C) 2016 Elsevier B.V. All rights reserved.

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