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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Topological superconductors exhibit unique Majorana edge states, analogous to Dirac edge states in topological insulators.
• One-dimensional topological superconductors are predicted to host Majorana fermions at their ends.
• Two-dimensional superconductors possess boundaries that can support propagating Majorana edge states with Dirac-like dispersion.

Purpose of the Study:

• To present evidence of one-dimensional dispersive in-gap edge states in a specific two-dimensional topological superconductor system.
• To interpret these observed states as a spatial topological transition involving gap closure.
• To propose a generalizable method for engineering topological quantum phases.

Main Methods:

• Fabrication of a heterostructure: a monolayer of lead (Pb) on magnetic cobalt-silicide (Co-Si) islands grown on a silicon (Si(111)) substrate.
• Experimental characterization to detect and analyze the properties of edge states.

Main Results:

• Observation of one-dimensional dispersive in-gap edge states.
• Interpretation of these states as evidence of a spatial topological transition with gap closure.
• Demonstration of a Pb/Co-Si/Si(111) system as a platform for topological superconductivity.

Conclusions:

• The study provides experimental evidence for Majorana edge states in a 2D topological superconductor.
• The findings suggest a method for creating topological quantum phases by combining Rashba superconductors with magnetic layers.
• This platform holds potential for advancements in topological quantum computing and materials science.