Vladislav Pokorný
FZU – Institute of Physics, Czech Academy of Sciences

Magnetic molecules adsorbed on a superconductor show great potential for exploring electron interactions in controllable environments with promising applications in information processing and sensor technology. I present a study of molecular assemblies constructed from radical tetrabromo-tetraazapyrene molecules deposited on a superconducting Pb(111) surface in various geometries. Scanning tunneling spectroscopy reveals complicated behavior of Yu-Shiba-Rusinov (YSR) states within the superconducting gap including quantum phase transitions in single molecules, peak splitting in dimers and trimers and alternating charge patterns in short linear chains. The system is described using the impurity Anderson model with a superconducting bath. The model is solved using the numerical renormalization group technique, which provides a quantitative description of the experimental result, revealing the nature of the ground state and fully explains the behavior of the YSR states. I also discuss the possibility of using the tetramer assembly as an information unit, based on charge reorganization.

C. Li, V. Pokorný, P. Hapala et al., arXiv:2508.05575 (2025).
C. Li, V. Pokorný, M. Žonda et al., ACS Nano 19, 3403 (2025).