Two-dimensional topological superconductivity in Pb/Co/Si(111)

• Published in: Nature communications Vol. 8; no. 1
• Main Authors: Ménard, Gerbold, Guissart, Sébastien, Brun, Christophe, Leriche, Raphaël, Trif, Mircea, Debontridder, François, Demaille, Dominique, Roditchev, Dimitri, Simon, Pascal, Cren, Tristan
• Format: Journal Article
• Language: English
• Published: Nature Publishing Group 01.12.2017
• Subjects: Physics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02192-x

Abstract Just like insulators can present topological phases characterized by Dirac edge states, superconductors can exhibit topological phases characterized by Majorana edge states. In particular, one-dimensional topological superconductors are predicted to host zero-energy Majorana fermions at their extremities. By contrast, two-dimensional superconductors have a one-dimensional boundary which would naturally lead to propagating Majorana edge states characterized by a Dirac-like dispersion. In this paper we present evidences of one-dimensional dispersive in-gap edge states surrounding a two-dimensional topological superconducting domain consisting of a monolayer of Pb covering magnetic Co–Si islands grown on Si(111). We interpret the measured dispersive in-gap states as a spatial topological transition with a gap closure. Our method could in principle be generalized to a large variety of heterostructures combining a Rashba superconductor with a magnetic layer in order to be used as a platform for engineering topological quantum phases.