Bond-Order Potential for Erbium-Hydride System

Interatomic potentials for an Er-H system are derived based on an analytical bond-order scheme. The model potentials provide a good description of the bulk properties and defect properties of hcp-Er, including lattice parameters, cohesive energy, elastic constants, point defect formation energies, and surface and stacking fault energies. In addition to experimental data, an ab initio method is used to construct the necessary database of different phases. We demonstrate that such potentials can reproduce the hydrogen behavior in an a-phase Er-H system for a low hydrogen/metal ratio, Especially, the present potentials can be employed for modeling the energetics and structural properties of fcc ErH(2), including lattice parameters, elastic constants, bulk modulus, Young's modulus, shear modulus, as well as the formation energies and migration barriers of point defects in ErH(2).