Proximity effect between two superconductors spatially resolved by scanning tunneling spectroscopy

Abstract

We present a combined experimental and theoretical study of the proximity effect in an atomic-scale controlled junction between two different superconductors. Elaborated on a Si(111) surface, the junction comprises a Pb nanocrystal with an energy gap of 1.2 meV, connected to a crystalline atomic monolayer of lead with a gap of 0.23 meV. Using in situ scanning tunneling spectroscopy we probe the local density of states of this hybrid system both in space and in energy, at temperatures below and above the critical temperature of the superconducting monolayer. Direct and inverse proximity effects are revealed with high resolution. Our observations are precisely explained with the help of a self-consistent solution of the Usadel equations. In particular, our results demonstrate that in the vicinity of the Pb islands, the Pb monolayer locally develops a finite proximity-induced superconducting order parameter, well above its own bulk critical temperature. This leads to a giant proximity effect where the superconducting correlations penetrate inside the monolayer a distance much larger than in a non-superconducting metal.

13 pages, 14 figures, accepted for publication in Physical Review X

References in corpus (4)

• Phase controlled superconducting proximity effect probed by tunneling spectroscopy
• Density of states and supercurrent in diffusive SNS junctions: role of nonideal interfaces and spin-flip scattering
• Visualizing landscapes of the superconducting gap in heterogeneous superconductor thin films: geometric influences on proximity effects
• Scanning tunneling spectroscopy study of the proximity effect in a disordered two-dimensional metal

Cited by in corpus (31)

• Two-dimensional topological superconductivity in Pb/Co/Si(111)
• Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure
• Remarkable effects of disorder on superconductivity of single atomic layers of lead on silicon
• Evidence for time-reversal symmetry breaking of the superconducting state near twin-boundary interfaces in FeSe
• Isolated pairs of Majorana zero modes in a disordered superconducting lead monolayer
• Scanning Tunneling Spectroscopy of Proximity Superconductivity in Epitaxial Multilayer Graphene
• Spectroscopy of the superconducting proximity effect in nanowires using integrated quantum dots
• Efficient quasiparticle traps with low dissipation through gap engineering
• Induced spectral gap and pairing correlations from superconducting proximity effect
• Coherent Josephson thermodynamic cycles
• Enhancement and termination of the superconducting proximity effect due to atomic-scale defects visualized by scanning tunneling microscopy
• Proximity Effect Transfer from NbTi into a Semiconductor Heterostructure via Epitaxial Aluminum
• Proximity effect in normal-metal quasiparticle traps
• Andreev Reflection Spectroscopy of Topological Superconductor Candidate Nb${}_x$Bi${}_2$Se${}_3$
• PTCDA molecular monolayer on Pb thin films: An unusual π-electron Kondo system and its interplay with a quantum-confined superconductor
• Superconducting-superconducting hybridization for enhancing single-photon detection
• Closing the superconducting gap in small Pb-nanoislands with high magnetic fields
• Creating Nanostructured Superconductors On Demand by Local Current Annealing
• Supercurrents in chiral channels originate from upstream information transfer: a theoretical prediction
• Nonlocal superconducting quantum interference device
• Interface and bulk superconductivity in superconducting heterostructures with enhanced critical temperatures
• Superconducting proximity effect in flat band systems
• Local density of state fluctuations in 2D superconductor as a probe of quantum diffusion
• Secondary "Smile"-gap in the density of states of a diffusive Josephson junction for a wide range of contact types
• Density of states and current-voltage characteristics in SIsFS junctions
• Homointerface planar Josephson junction based on inverse proximity effect
• Observation of hidden parts of dislocation loops in thin Pb films by means of scanning tunneling spectroscopy
• Self-consistent evaluation of proximity and inverse proximity effects with pair-breaking in diffusive SN junctions
• Local density of states in clean two-dimensional superconductor--normal metal--superconductor heterostructures
• Oscillatory Bias Dependence of Visible Height of Monatomic Pb(111) Steps: Consequence of Quantum-Size Effect for Thin Metallic Films
• Anomalous superconducting proximity effect of planar Pb-RhPb2 heterojunctions in the clean limit