InSbAs Two-Dimensional Electron Gases as a Platform for Topological Superconductivity

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 angstrom, thus exceeding typical values measured in its binary constituents. In addition to a large Lande g-factor of similar to 55 (comparable to that of 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.

Automated summary

Experimental results show that topological superconductivity can be engineered in semiconductors with strong spin-orbit interaction by coupling them to a superconductor. The 2D platform based on a ternary 2DEG (InSbAs) coupled to in situ grown aluminum allows for the tuning of spin-orbit coupling and the demonstration of phase-controllable Josephson junctions and superconducting islands. The clean superconductor-semiconductor interface in this system leads to a hard induced superconducting gap, providing a promising platform for studying Majorana zero modes.