Electronic properties of InAs/EuS/Al hybrid nanowires

TL;DR

This study combines spectroscopic experiments and microscopic simulations to understand the electronic properties of InAs/EuS/Al nanowires, revealing conditions for topological superconductivity driven by magnetic proximity effects.

Contribution

It provides a detailed analysis of band bending, interface effects, and the topological phase diagram in hybrid nanowires, emphasizing the importance of combined experimental and theoretical approaches.

Findings

Magnetic proximity effects are crucial for topological superconductivity.

The topological phase can be optimized via external gating.

Realistic parameters allow for topological superconductivity in the hybrid nanowire.

Abstract

We study the electronic properties of InAs/EuS/Al heterostructures as explored in a recent experiment [S. Vaitiekenas \emph{et al.}, Nat. Phys. (2020)], combining both spectroscopic results and microscopic device simulations. In particular, we use angle-resolved photoemission spectroscopy to investigate the band bending at the InAs/EuS interface. The resulting band offset value serves as an essential input to subsequent microscopic device simulations, allowing us to map the electronic wave function distribution. We conclude that the magnetic proximity effects at the Al/EuS as well as the InAs/EuS interfaces are both essential to achieve topological superconductivity at zero applied magnetic field. Mapping the topological phase diagram as a function of gate voltages and proximity-induced exchange couplings, we show that the ferromagnetic hybrid nanowire with overlapping Al and EuS layers can become a topological superconductor within realistic parameter regimes, and that the topological phase can be optimized by external gating. Our work highlights the need for a combined experimental and theoretical effort for faithful device simulation.