Charge of a quasiparticle in a superconductor

Abstract

Non-linear charge transport in SIS Josephson junctions has a unique signature in the shuttled charge quantum between the two superconductors. In the zero-bias limit Cooper pairs, each with twice the electron charge, carry the Josephson current. An applied bias $V_{SD}$ leads to multiple Andreev reflections (MAR), which in the limit of weak tunneling probability should lead to integer multiples of the electron charge $ne$ traversing the junction, with $n$ integer larger than $2\Delta /e{V}_{SD}$ and $\Delta$ the superconducting order parameter. Exceptionally, just above the gap, $e{V}_{SD}>2\Delta$, with Andreev reflections suppressed, one would expect the current to be carried by partitioned quasiparticles; each with energy dependent charge, being a superposition of an electron and a hole. Employing shot noise measurements in an SIS junction induced in an InAs nanowire (with noise proportional to the partitioned charge), we first observed quantization of the partitioned charge $q=e^{\ast }/e=n$, with $n=1-4$; thus reaffirming the validity of our charge interpretation. Concentrating next on the bias region $e{V}_{SD}\approx 2\Delta$, we found a reproducible and clear dip in the extracted charge to $q\approx 0.6$, which, after excluding other possibilities, we attribute to the partitioned quasiparticle charge. Such dip is supported by numerical simulations of our SIS structure.

References in corpus (1)

• Multi-mode Fabry-Pérot conductance oscillations in suspended stacking-faults-free InAs nanowires

Cited by in corpus (35)

• Electron pairing in the pseudogap state revealed by shot noise in copper-oxide junctions
• Non-local Supercurrent of Quartets in a Three-Terminal Josephson Junction
• Shot Noise in Mesoscopic Systems: from Single Particles to Quantum Liquids
• Direct evidence for Cooper pairing without a spectral gap in a disordered superconductor above $T_C$
• Local noise in a diffusive conductor
• Proximity superconductivity in atom-by-atom crafted quantum dots
• Magic angles and correlations in twisted nodal superconductors
• Wave packet dynamics of Bogoliubov quasiparticles: quantum metric effects
• Amplifier for scanning tunneling microscopy at MHz frequencies
• Atomic scale shot-noise using broadband scanning tunnelling microscopy
• Current- and field-induced topology in twisted nodal superconductors
• Imaging doubled shot noise in a Josephson scanning tunneling microscope
• Does shot noise always provide the quasiparticle charge?
• Charge, spin, and heat shot noises in the absence of average currents: Conditions on bounds at zero and finite frequencies
• Coherent and incoherent tunneling into YSR states revealed by atomic scale shot-noise spectroscopy
• G4CMP: Condensed Matter Physics Simulation Using the Geant4 Toolkit
• Charge trapping and super-Poissonian noise centers in a cuprate high-temperature superconductor
• MBE growth of self-assisted InAs nanowires on graphene
• Quantized conductance with non-zero shot noise as a signature of Andreev edge state
• Heat-mode excitation in a proximity superconductor
• Noise insights into electronic transport
• Enhanced shot noise at bilayer graphene -- superconductor junction
• Real-space multiple scattering theory for superconductors with impurities
• Out-of-Equilibrium Spin Transport in Mesoscopic Superconductors
• Local-noise spectroscopy for non-equilibrium systems
• Time-dependent Andreev reflection
• Signatures of odd-frequency pairing in the Josephson junction current noise
• Shot-noise measurements of single-atom junctions
• Why shot noise does not generally detect pairing in mesoscopic superconducting tunnel junctions
• Noise of a chargeless Fermi liquid
• Photon assisted tunneling of high order multiple Andreev reflections in epitaxial nanowire Josephson junctions
• Magnetic impurities on superconducting Pb surfaces
• Giant shot noise in superconductor/ferromagnet junctions with orbital-symmetry-controlled spin-orbit coupling
• Local thermometry of NbSe${}_2$ flake with delta-$T$ noise measurements
• Microwave radiometry of a quantum-critical, hybrid Josephson array