Toward Gate-Tunable Topological Superconductivity in a Supramolecular Electron Spin Lattice

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Low-dimensional magnet/superconductor hybrid systems are promising for realizing topological superconductivity.
• Achieving control over molecular spin states on superconducting surfaces is crucial for exploring exotic quantum phenomena.

Purpose of the Study:

• To demonstrate the supramolecular assembly of organic radicals on a superconducting substrate (Pb(111)).
• To investigate the emergence of topological superconductivity in organic/superconductor hybrid systems.

Main Methods:

• Utilized scanning tunneling microscopy (STM) to control the charge state of organic radicals on Pb(111).
• Analyzed Yu-Shiba-Rusinov (YSR) subgap states in tunneling spectra to confirm spin-1/2 states and lattice formation.
• Performed tight-binding simulations to interpret the spectral signatures and localization of edge states.

Main Results:

• Successfully assembled organic radicals on superconducting Pb(111), forming a two-dimensional spin lattice with tunable anionic states.
• Observed YSR subgap states, confirming the presence of localized spin-1/2 moments.
• Identified low-energy subgap states localized at the edges of molecular domains, consistent with topologically protected modes.

Conclusions:

• The study demonstrates a viable route for creating organic/superconductor hybrid systems for topological superconductivity.
• The observed edge states suggest the potential realization of topologically protected quantum phenomena in these engineered systems.
• This research paves the way for designing novel materials for future topological quantum applications.