運動する転位に対する flexible boundary condition

概要

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The displacement field around the dislocation is a long range field which falls away inversely with distance from the dislocation line, so that, with rigid boundary condition, the imaginary force from the boundary affects the result in the simulation for dislocation. Flexible boundary condition for static dislocation has developed to avoid such boundary effect. With the flexible boundary condition, the displacements of atoms in the boundary region change according to the state of whole system. Various modified versions of the boundary conditions have been applied to the calculations of the core structures of the dislocations and the Peierls stresses. Now, new flexible boundary condition is obtained for the moving straight dislocation, which is introduced by Lagrangian principle. As an example, the glide motion of the screw dislocation are simulated on a two dimensional lattice with the flexible and the rigid boundary conditions. The effects of model size, boundary conditions, and potential will be discussed. The results of the system with low Peierls stress with the flexible boundary condition are independent of the model size used in the simulations, and in agreement with the large rigid boundary model.
九州大学の論文