InSbAs two-dimensional electron gases as a platform for topological superconductivity

TL;DR

This paper presents a tunable InSbAs 2DEG platform coupled with aluminum, enabling the realization of topological superconductivity and Majorana modes through advanced hybrid device architectures.

Contribution

It introduces a new InSbAs 2DEG system with tunable spin-orbit coupling and high-quality interfaces for topological superconductivity research.

Findings

Tunable spin-orbit coupling up to 400 meVÅ in InSbAs 2DEGs.

Hard induced superconducting gap at superconductor-semiconductor interface.

Successful demonstration of Josephson junctions and superconducting islands.

Abstract

Topological superconductivity can be engineered in semiconductors with strong spin-orbit interaction coupled to a superconductor. Experimental advances in this field have often been triggered by the development of new hybrid material systems. Among these, two-dimensional electron gases (2DEGs) are of particular interest due to their inherent design flexibility and scalability. Here we discuss results on a 2D platform based on a ternary 2DEG (InSbAs) coupled to in-situ grown Aluminum. The spin-orbit coupling in these 2DEGs can be tuned with the As concentration, reaching values up to 400 meV$\unicode{xC5}$, thus exceeding typical values measured in its binary constituents. In addition to a large Land\'e g-factor $\sim$ 55 (comparable to InSb), we show that the clean superconductor-semiconductor interface leads to a hard induced superconducting gap. Using this new platform we demonstrate the basic operation of phase-controllable Josephson junctions, superconducting islands and quasi-1D systems, prototypical device geometries used to study Majorana zero modes.