Parallel dislocation simulator

For a given material, this input takes the form of an activation enthalpy versus shear stress curve and phonon-drag coefficients calculated for each pressure under consideration. Here full activation enthalpy curves have been calculated at selected pressures in Ta, Mo, and V, and phonon drag has been studied as a function of pressure and temperature in the case of Ta. These results have been fitted and modeled in suitable analytic forms to interface smoothly with the DD simulation codes. Detailed DD simulations have then been carried out in Ta and Mo as a function of pressure, temperature, and strain rate. Our DD simulations have been performed in part with the pioneering lattice-based serial code developed for bcc metals [21,22] but even more extensively with the general node-based Parallel Dislocation Simulator (ParaDiS) code recently developed at the Lawrence Livermore National Laboratory [27-30]. 

The advantage of being able to record diffraction intensities over a range of incident beam directions makes CBED readily accessible for comparison with simulations. Thus, CBED is a quantitative diffraction technique. In past 15 years, CBED has evolved from a tool primarily for crystal symmetry determination to the most accurate technique for strain and structure factor measurement [16]. For defects, large angle CBED technique can characterize individual dislocations, stacking faults and interfaces. For applications to defect structures and structure without three-dimensional periodicity, parallel-beam illumination with a very small beam convergence is required. 

Figure 9.5 Simulated rocking topograph of misfit dislocations parallel to the surface of a (OOl)-oriented GaAs wafer. Dislocation line runs up the page...

Fig. 12.26. Results of mesoscopic dislocation dynamics simulation of dislocation interactions in a strained epitaxial layer (adapted from Schwarz and LeGoues (1997)). The network shown in the figure results from the interaction of dislocations on parallel glide planes.

Fig. 2. Schematic representation of the domain decomposition scheme used to implement flexible Green s function boundary conditions in our GFBC/MGPT atomistic simulation code for dislocation calculations, (a) The three main computational regions separated into a layered

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