Majorana bound states in a coupled quantum-dot hybrid-nanowire system

TL;DR

This paper demonstrates the creation and detection of Majorana bound states in a hybrid nanowire system, showing how ABSs evolve into MBSs under magnetic field and their hybridization with quantum dot states.

Contribution

It provides experimental evidence of MBS emergence from ABSs in a hybrid nanowire with a quantum dot spectrometer, advancing understanding of topological superconductivity.

Findings

MBS emerge from coalescing ABSs under magnetic field

Hybridization of MBS with end-dot states observed

Spectral parameters inform topological superconductor models

Abstract

Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using a quantum dot at the end of the nanowire as a spectrometer. Electrostatic gating tuned the nanowire density to a regime of one or a few ABSs. In an applied axial magnetic field, a topological phase emerges in which ABSs move to zero energy and remain there, forming MBSs. We observed hybridization of the MBS with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system.