Discharge and Electron Correlation of Radical Molecules in a Supramolecular Assembly on Superconducting Pb(111)

Abstract

Precise control over the charge-state of radical molecules on surfaces is essential for engineering correlated electronic states in nanoscale architectures. Here, we demonstrate the supramolecular assembly of tetraazapyrene-based radicals on superconducting Pb(111), where anionic species formed by charge transfer from the substrate coexist with their neutral counterparts. These radicals can be discharged via capacitive coupling with the local electric field of the scanning probe tip, producing peaks (dips) in tunneling (force) spectra. Spatial mapping further reveals cascade discharging events and electron correlation between adjacent molecules of the lattice. Through tip-induced debromination, we achieve irreversible discharge enabling the creation of defect patterns. Our results establish a pathway towards gate-tunable spin arrays with ultra-high areal density, leveraging charge-state control and emergent electron correlations in molecular assemblies.