Conductance asymmetries in mesoscopic superconducting devices due to finite bias

Abstract

Tunneling conductance spectroscopy in normal metal-superconductor junctions is an important tool for probing Andreev bound states in mesoscopic superconducting devices, such as Majorana nanowires. In an ideal superconducting device, the subgap conductance obeys specific symmetry relations, due to particle-hole symmetry and unitarity of the scattering matrix. However, experimental data often exhibits deviations from these symmetries or even their explicit breakdown. In this work, we identify a mechanism that leads to conductance asymmetries without quasiparticle poisoning. In particular, we investigate the effects of finite bias and include the voltage dependence in the tunnel barrier transparency, finding significant conductance asymmetries for realistic device parameters. It is important to identify the physical origin of conductance asymmetries: in contrast to other possible mechanisms such as quasiparticle poisoning, finite-bias effects are not detrimental to the performance of a topological qubit. To that end we identify features that can be used to experimentally determine whether finite-bias effects are the source of conductance asymmetries.

19 pages, 10 figures

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Cited by in corpus (13)

• Nontopological zero-bias peaks in full-shell nanowires induced by flux tunable Andreev states
• Local and non-local quantum transport due to Andreev bound states in finite Rashba nanowires with superconducting and normal sections
• Parity protected superconducting diode effect in topological Josephson junctions
• Trivial Andreev band mimicking topological bulk gap reopening in the non-local conductance of long Rashba nanowires
• Nonlocal conductance spectroscopy of Andreev bound states in gate-defined InAs/Al nanowires
• Theory of Caroli-de Gennes-Matricon analogs in full-shell hybrid nanowires
• Driven Andreev molecule
• Multiterminal transport spectroscopy of subgap states in Coulomb-blockaded superconductors
• Probing electron-hole weights of an Andreev bound state by transient currents
• Electron-boson-interaction induced particle-hole symmetry breaking of conductance into subgap states in superconductors
• Transport features of a topological superconducting nanowire with a quantum dot: conductance and noise
• Spin-resolved nonlocal transport in proximitized Rashba nanowires
• Conductance matrix symmetries of multiterminal semiconductor-superconductor devices