A finite-temperature coarse-grained atomistic approach for understanding the kink-controlled dynamics of micrometer-long dislocations in high-Peierls-barrier materials

Unifying temperature definition in atomistic and field representations of conservation laws

“…Note that cross-kinking and debris formation are largely suppressed in (b) as a result of coarse graining that ignores the short-wavelength vibrations. For more simulation results and discussions, see [55,56].…”

“…To extend the CAC method for finite temperature processes, equation (5.12) has been tested though implementation in the CAC codes using a modified finite-element method with tri-linear shape functions [53–55]. To test the formulation and numerical implementations, we build four sets of computer models that are discretized with 8-node rhombohedral elements, with each element containing 8×8×8 primitive unit cells and the surfaces of the elements corresponding to the slip and/or the cleavage planes of the crystals.…”

“…This means that all the phonon frequencies that are captured in the MD simulations are present in the CAC simulations. For more verification examples and discussions, see [55].

Figure 6MD and CAC results of normalized PDOS of a Si crystal model ( a ) and an Fe crystal ( b ) with 512 unit cells in each FE.

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“…This means that all the phonon frequencies that are captured in the MD simulations are present in the CAC simulations. For more verification examples and discussions, see [56].…”

“…Note that cross-kinking and debris formation are largely suppressed in (b) as a result of coarse graining that ignores the short-wavelength vibrations. For more simulation results and discussions, see [54,55].

Figure 8Time sequences of a segment of the dislocation line to illustrate the atomistic process of ( a ) self-pinning and ( b ) debris loop formation that result from cross-kinks of a 2968-nm-long dislocation line.

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