Final CAI abundance profile after 5 Myr with variations of α_peak, which controls the depth of the planet gap. Higher values increase the gradient in the gas surface density and hence lead to a stronger pressure gradient pushing CAIs back towards the pressure bump. This reduces the amount of CAIs passing through and thus lowers the CAI abundance in the region in between the two planets. A rapid transition seems to occur between α_peak = 1 × 10⁻⁴ and 2 × 10⁻⁴.