Suppressing Andreev bound state zero bias peaks using a strongly dissipative lead

TL;DR

This study demonstrates that introducing a strongly resistive lead in semiconductor-superconductor nanowires suppresses zero-bias peaks caused by Andreev bound states, aiding in the identification of Majorana zero modes.

Contribution

It provides the first experimental evidence of dissipative suppression of Andreev bound states using a resistive lead, offering a new method to refine Majorana zero mode detection.

Findings

Most zero-bias peaks were suppressed by the resistive lead

Environmental Coulomb blockade effectively filters Andreev bound states

Potential to improve Majorana zero mode identification

Abstract

Hybrid semiconductor-superconductor nanowires are predicted to host Majorana zero modes, manifested as zero-bias peaks (ZBPs) in tunneling conductance. ZBPs alone, however, are not sufficient evidence due to the ubiquitous presence of Andreev bound states in the same system. Here, we implement a strongly resistive normal lead in our InAs-Al nanowire devices and show that most of the expected ZBPs, corresponding to zero-energy Andreev bound states, can be suppressed, a phenomenon known as environmental Coulomb blockade. Our result is the first experimental demonstration of this dissipative interaction effect on Andreev bound states and can serve as a possible filter to narrow down ZBP phase diagram in future Majorana searches.