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Simulation of macroscopic systems with non-vanishing elastic dipole components

Simulation de systèmes macroscopiques possédant des composantes dipolaires élastiques non nulles

Abstract : To simulate a macroscopic system from a simulation cell, a direct summation of the elastic fields produced by periodic images can be used. If the cell contains a non-zero elastic dipole component, the sum is known to be conditionally convergent. In analogy with systems containing electric or magnetic dipoles, we show that the sum introduces a component which only depends on the shape of the summation domain and on the dipole density. A correction to the direct summation is proposed for the strain and stress fields in the simulation cell, which ensures that zero tractions are imposed on the boundary of the macro-scopic system. The elastic fields then do not depend anymore on the shape of the domain. The effect of this correction is emphasized on the kinetics of dislo-cation loop growth by absorption of point defects. It is shown that correcting elastic fields has an influence on the kinetics if defects have different properties at stable and saddle points.