On the other hand, for the two semi-circles observed at potentials lower than 0.15 VRHE, we used the matryoshka circuit (Figure ), comprising two resistive (Rrec1 and Rrec2) and two capacitive (Cdep and Cinter) elements. It should be noted that the matryoshka circuit is mathematically equivalent to the simple Voight circuit in the case of C1 << C2, and in our case fitting with both circuits gives us the same values of the R-C elements and therefore the same time constants. Nevertheless, the matryoshka circuit is more appropriate here because our interpretation of the R-C elements indicates that the underlying physical phenomena influence each other (the Voight circuit would be applicable for two separate phenomena occurring one after the other).