*3.2. Kinetics of Lattice-Trapped Delamination*

To characterize the kinetics of lattice-trapped delamination, we extracted the crack growth rate in terms of the rate of increase of the crack volume as shown in Figure 6. Since no other defects were present in the simulation cell, it is expected that essentially all increases in volume must be due to growth of interfacial cracks. Visual inspection of simulations and identification of volume "hot spots" where atomic volumes were elevated confirmed this assumption; we never observed significant volume increases in the bulk, only at the interface near cracks. It is more conventional, of course, to characterize a crack in terms of its area or radius. However, since cracks typically adopted complex shapes and morphologies, it was difficult to directly extract their area and/or radius. For these reasons, we use changes in simulation cell volume to quantify the delamination rate.

We determined the lattice-trapped delamination rate by taking a linear regression of the volume vs. time curve from the start of the load holding phase to the time of dislocation nucleation, shown by the dashed lines in Figure 6. We find that under the same nominal conditions (stress and temperature), the delamination rate was sensitive to the initial conditions (e.g., initial random atomic velocities). For this reason, 10 replicate simulations were performed at each condition. Figure 7 shows histograms of the lattice-trapped delamination rate at a few conditions with 30 replica simulations, demonstrating the spread of the data. Interestingly, the delamination rates are systematically biased towards lower rates (rather than being symmetrical about the mean), qualitatively taking the form of exponential distributions. Figure 8 shows the mean delamination rate as a function of *σ<sup>H</sup>* at temperatures of 200, 250, 300, 350, and 400 K. There is clearly a strong sensitivity to both stress and temperature. We will further analyze these data in the Discussion.

**Figure 7.** Histograms of lattice-trapped delamination rates from 30 replicas at (**a**) *T* = 200 K and *σ<sup>H</sup>* = 7.0 GPa and (**b**) *T* = 400 K and *σ<sup>H</sup>* = 6.0 GPa.

**Figure 8.** Average lattice-trapped delamination rate among 10 replicas, . *V*, as a function of hydrostatic stress over temperatures ranging from 200 to 400 K.
