  The interfacial nature of the electric double layer (EDL) assumes that
electrode surface morphology significantly impacts the EDL properties. Since
molecular-scale roughness modifies the structure of EDL, it is expected to
disturb the overscreening effect and alter differential capacitance (DC). In
this Letter, we present a model that describes EDL near atomically rough
electrodes with account for short-range electrostatic correlations. We provide
numerical and analytical solutions for the analysis of conditions for the
overscreening breakdown and DC shift estimation. Our findings reveal that
electrode surface structure leads to DC decrease and can both brake or enhance
overscreening depending on the relation of surface roughness to electrostatic
correlation length and ion size asymmetry.
