Parametric exploration of zero-energy modes in three-terminal InSb-Al nanowire devices

TL;DR

This study systematically explores zero-energy states in three-terminal InSb-Al nanowire devices using radio-frequency reflectometry, providing a new measurement approach to distinguish trivial states from potential Majorana modes.

Contribution

It introduces a comprehensive measurement strategy that reduces false positives in identifying topological phases in hybrid nanowires.

Findings

Identified non-coexisting states ruling out topological phases in large parameter regions.

Demonstrated filtering of zero-energy states sensitive to local gate potentials.

Provided diagrams showing state evolution as a function of experimental parameters.

Abstract

We systematically study three-terminal InSb-Al nanowire devices by using radio-frequency reflectometry. Tunneling spectroscopy measurements on both ends of the hybrid nanowires are performed while systematically varying the chemical potential, magnetic field and junction transparencies. Identifying the lowest-energy state allows for the construction of lowest- and zero-energy state diagrams, which show how the states evolve as a function of the aforementioned parameters. Importantly, comparing the diagrams taken for each end of the hybrids enables the identification of states which do not coexist simultaneously, ruling out a significant amount of the parameter space as candidates for a topological phase. Furthermore, altering junction transparencies filters out zero-energy states sensitive to a local gate potential. Such a measurement strategy significantly reduces the time necessary to identify a potential topological phase and minimizes the risk of falsely recognizing trivial bound states as Majorana zero modes.