Proximity-induced Shiba states in a molecular junction

Abstract

Superconductors containing magnetic impurities exhibit intriguing phenomena derived from the competition between Cooper pairing and Kondo screening. At the heart of this competition are the Yu-Shiba-Rusinov (Shiba) states which arise from the pair breaking effects a magnetic impurity has on a superconducting host. Hybrid superconductor-molecular junctions offer unique access to these states but the added complexity in fabricating such devices has kept their exploration to a minimum. Here, we report on the successful integration of a model spin 1/2 impurity, in the form of a neutral and stable all organic radical molecule, in proximity-induced superconducting break-junctions. Our measurements reveal excitations which are characteristic of a spin-induced Shiba state due to the radical's unpaired spin strongly coupled to a superconductor. By virtue of a variable molecule-electrode coupling, we access both the singlet and doublet ground states of the hybrid system which give rise to the doublet and singlet Shiba excited states, respectively. Our results show that Shiba states are a robust feature of the interaction between a paramagnetic impurity and a proximity-induced superconductor where the excited state is mediated by correlated electron-hole (Andreev) pairs instead of Cooper pairs.

29 pages including supporting information

References in corpus (7)

• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Hard gap in epitaxial semiconductor-superconductor nanowires
• Zero-bias anomaly in a nanowire quantum dot coupled to superconductors
• Tuning the Kondo effect with a mechanically controllable break junction
• Shiba states and zero-bias anomalies in the hybrid normal-superconductor Anderson model
• Transport Measurement of Andreev Bound States in a Kondo-Correlated Quantum Dot

Cited by in corpus (12)

• Yu-Shiba-Rusinov states of impurities in a triangular lattice of NbSe${}_2$ with spin orbit coupling
• Pair excitations of a quantum spin on a proximitized superconductor
• Extending the spin excitation lifetime of a magnetic molecule on a proximitized superconductor
• Nanoscale Control of Quantum States in Radical Molecules on Superconducting Pb(111)
• Interplay between Majorana and Shiba states in a minimal Kitaev chain coupled to a superconductor
• Yu-Shiba-Rusinov States and Ordering of Magnetic Impurities Near the Boundary of a Superconducting Nanowire
• Diamagnetic property and optical absorption in conventional superconductors with magnetic impurities
• Theory of a Single Magnetic Impurity on a Thin Metal Film in Proximity to a Superconductor
• Subgap states in semiconductor-superconductor devices for quantum technologies: Andreev qubits and minimal Majorana chains
• Probing Magnetic and Triplet Correlations in Spin-Split Superconductors with Magnetic Impurities
• Robust Spin Polarization of Yu-Shiba-Rusinov States in Superconductor/Ferromagnetic Insulator Heterostructures
• Andreev bound states in Superconductor-quantum dot Josephson junction at infinite-U limit