*4.2. Simulation Configuration of Experiments*

Combined with the discussion of image stress effects [41,44], the slip step heights due to a dislocation pile-up measured in experiments (see Figure 5c for Ni and Figure 6c for *α*-Brass) can be simulated in a bi-crystal configuration containing a GB and two free surfaces using a discrete dislocation pile-up modelling in heterogeneous anisotropic elasticity. The hypotheses and configurations are set as follows and presented in Figure 7:


$$
\Delta h(d) = N(d) \times b(Z) \tag{2}
$$

where *d* is the distance from GB along slip direction, *N* the number of dislocations in the dislocation pile-up from GB to the position *d*, and *b*(Z) is the out-of-surface component of the Burgers vector (along Z direction, which is perpendicular to the upper surface as shown in Figure 7b).

9. In the following parts, the measured slip step height is calibrated to be zero at GB, which means <sup>Δ</sup>*<sup>h</sup>* = *<sup>h</sup>*Top − *<sup>h</sup>*Bottom − <sup>Δ</sup>*h*GB. Similarly, the simulated slip step height profile is considered to be zero at GB as Δ*h*(0) = 0.
