Non-equilibrium theory of tunneling into localized state in superconductor

Abstract

A single static magnetic impurity in a fully-gapped superconductor leads to formation of an intragap quasiparticle bound state. At temperatures much below the superconducting transition, the energy relaxation and spin dephasing of the state are expected to be exponentially suppressed. The presence of such a state can be detected in electron tunneling experiments as a pair of conductance peaks at positive and negative biases. Here we show, that for an arbitrarily weak tunneling strength, the peaks have to be symmetric with respect to the applied bias. This is in contrast to the standard result that the tunneling conductance is proportional to the local (in general particle-hole asymmetric) density of states. The asymmetry can be recovered is one allows for either a finite density of impurity states, or that impurities are coupled to another, non-superconducting, equilibrium bath.

5 pages

References in corpus (3)

• Zero-bias anomaly in a nanowire quantum dot coupled to superconductors
• Numerical Renormalization Group Approach to a Quantum Dot Coupled to Normal and Superconducting Leads
• Nonequilibrium transport via spin-induced sub-gap states in superconductor/quantum dot/normal metal cotunnel junctions

Cited by in corpus (20)

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• Zero-energy pinning of topologically-trivial bound states in multi-band semiconductor-superconductor nanowires
• Tunneling dynamics between superconducting bound states at the atomic limit
• Robust Majorana conductance peaks for a superconducting lead
• Interplay Between Yu-Shiba-Rusinov States and Multiple Andreev Reflections
• Robustness of Yu-Shiba-Rusinov resonances in presence of a complex superconducting order parameter
• Conductance feature smearing and anisotropic suppression of induced superconductivity in a Majorana nanowire
• Direct Transport between Superconducting Subgap States in a Double Quantum Dot
• Conductance asymmetries in mesoscopic superconducting devices due to finite bias
• Tunneling conductance in semiconductor-superconductor hybrid structures
• Nonreciprocal superconductivity
• Temperature Induced Shifts of Yu-Shiba-Rusinov Resonances in Nanowire-Based Hybrid Quantum Dots
• Electron-boson-interaction induced particle-hole symmetry breaking of conductance into subgap states in superconductors
• Identifying Majorana vortex modes via non-local transport
• Dynamical Shiba states by precessing magnetic moments in an s-wave superconductor
• Tunneling spectra of impurity states in unconventional superconductors
• Conductance matrix symmetries of multiterminal semiconductor-superconductor devices