Abstract
Recent tunneling spectroscopy experiments in semiconducting nanowires with proximity-induced superconductivity have reported robust zero-bias conductance peaks. Such a feature can be compatible with the existence of topological Majorana bound states (MBSs) and with a trivial Andreev bound state (ABS) near zero energy. Here, we argue that additional information, that can distinguish between the two cases, can be extracted from Coulomb blockade experiments of Majorana islands. The key is the ratio of peak heights of consecutive conductance peaks gives information about the electron and hole components of the lowest-energy subgap state. In the MBS case, this ratio goes to one-half for long wires, whereas for short wires with finite MBS overlap it oscillates a function of Zeeman energy with the same period as the MBS energy splitting. We explain how the additional information might help to distinguish a trivial ABS at zero energy from a true MBS and show case examples.
- Received 22 December 2017
- Revised 12 January 2018
DOI:https://doi.org/10.1103/PhysRevB.97.041411
©2018 American Physical Society