3. Perisuperficial distribution of the electronic load

3.1 Metal surfaces

The surface of a crystalline solid, by breaking the three-dimensional periodicity of the infinite crystal, introduces significant modifications to the electronic structure in its vicinity. The electronic states of an infinite periodic solid are Bloch waves (3D) delocalized throughout the solid, but the presence of a surface will reflect the incident Bloch waves inwards. The result is standing waves inside the solid, which cancel out at the surface considered as an infinite potential barrier to the vacuum, implying zero charge density at the edge (in z = 0). Towards the interior of the solid, the charge density converges to its volume value within a peeling length that is of the order of a quarter of the smallest electronic (de Broglie) wavelength, i.e. the Fermi...