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Conductance asymmetries in mesoscopic superconducting devices due to finite bias
by André Melo, Chun-Xiao Liu, Piotr Rożek, Tómas Örn Rosdahl, Michael Wimmer
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | André Melo · Michael Wimmer |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2008.01734v2 (pdf) |
| Code repository: | https://zenodo.org/record/3971803 |
| Data repository: | https://zenodo.org/record/3971803 |
| Date accepted: | 2021-02-02 |
| Date submitted: | 2021-01-28 10:52 |
| Submitted by: | Melo, André |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
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.
Author comments upon resubmission
List of changes
- Corrected the $W$ matrix (eq. 13) to ensure it has particle-hole symmetry. While this change leads to a different expression for the intermediate result in eq. 14, all other results remain valid.
- Added clarification and fixes mentioned in replies to referee reports.
Published as SciPost Phys. 10, 037 (2021)