Cover Picture: Silicene on hydrogen‐passivated Si(111) and Ge(111) substrates (Phys. Status Solidi RRL 8/2013)

Several researchers claim to have produced silicene, the graphene-like allotrope of silicon, that could result in the ultimate miniaturization of the Si-device technology and in novel electronic and optical properties due to the appearance of massless Dirac electrons. It is sometimes described as a new “wonder material”. Favored substrates are Ag(111) and Ir(111) metal surfaces. However, the growth of silicene layers is a huge challenge. Recent theoretical and experimental studies show a destruction of the Dirac cones due to a lowering of the honeycomb symmetry and the strong interaction with the substrate. In the Letter by Kokott, Matthes, and Bechstedt (pp. 538–541) the possibility of the silicene formation on hydrogen-passivated Si(111) (as displayed on the front cover) and Ge(111) surfaces is predicted. The stability of a silicene sheet and its exceptional electronic properties are demonstrated by first-principles studies. The van-der-Waals interaction bonds the silicene layer to the inert substrates. Because of the reduced chemical interaction the linear conical bands near the corner points of the hexagonal Brillouin zone survive with an extremely small energy gap.