Superconducting parity effect across the Anderson limit

Abstract

How small superconductors can be? For isolated nanoparticles subject to quantum size effects, P.W. Anderson conjectured in 1959 that superconductivity could only exist when the electronic level spacing $\delta$ is smaller than the superconducting gap energy $\Delta$. Here, we report a scanning tunneling spectroscopy study of superconducting lead (Pb) nanocrystals grown on the (110) surface of InAs. We find that for nanocrystals of lateral size smaller than the Fermi wavelength of the 2D electron gas at the surface of InAs, the electronic transmission of the interface is weak; this leads to Coulomb blockade and enables the extraction of the electron addition energy of the nanocrystals. For large nanocrystals, the addition energy displays superconducting parity effect, a direct consequence of Cooper pairing. Studying this parity effect as function of nanocrystal volume, we find the suppression of Cooper pairing when the mean electronic level spacing overcomes the superconducting gap energy, thus demonstrating unambiguously the validity of the Anderson criterion.

arXiv comment25 pages, 5 figures in main articles, 9 in supplementary

References in corpus (13)

• Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
• Exponential Protection of Zero Modes in Majorana Islands
• The Statistical Theory of Quantum Dots
• Quantum Effects in Coulomb Blockade
• Spectroscopy of discrete energy levels in ultrasmall metallic grains
• Coulomb blockade at almost perfect transmission
• Nonequilibrium quasiparticles and $2e$ periodicity in single-Cooper-pair transistors
• Parity lifetime of bound states in a proximitized semiconductor nanowire
• Observation of shell effects in superconducting nanoparticles of Sn
• 1 minute parity lifetime of a NbTiN Cooper-pair transistor
• Experimental demonstration of a two-band superconducting state for lead using scanning tunneling spectroscopy
• Magnetization of small lead particles
• Parity effect in Al and Nb single electron transistors in a tunable environment

Cited by in corpus (10)

• Excitations in a superconducting Coulombic energy gap
• Confinement-engineered superconductor to correlated-insulator transition in a van der Waals monolayer
• Quantum confinement effects in Pb Nanocrystals grown on InAs
• Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands
• STM observation of the hinge-states of bismuth nanocrystals
• Lateral quantum confinement effect on monolayer high-Tc superconductors
• Superconductivity in correlated carbon nanotubes under pressure: A Bogoliubov-de Gennes study
• Subgap states in superconducting islands
• Dynamical Coulomb Blockade as a Signature of the Sign-Reversing Cooper Pairing Potential
• Imaging asymmetric Coulomb blockade phenomena across metallic nanoislands