Engineering topological superconductors using surface atomic-layer/molecule hybrid materials

Surface atomic-layer (SAL) superconductors consisting of epitaxially grown metal adatoms on a clean semiconductor surface have been recently established. Compared to conventional metal thin films, they have two important features: i) space-inversion symmetry breaking throughout the system and ii) high sensitivity to surface adsorption of foreign species. These potentially lead to manifestation of the Rashba effect and a Zeeman field exerted by adsorbed magnetic organic molecules. After introduction of archetypical SAL superconductor Si(111)-(root7xroot3)-In, we describe how these features are utilized to engineer topological superconductor with Majorana fermions, and discuss its promises and expected challenges.