Two-dimensional epitaxial superconductor-semiconductor heterostructures: A platform for topological superconducting networks

TL;DR

This paper reports the development of a two-dimensional epitaxial superconductor-semiconductor heterostructure with high-quality interfaces, enabling the creation of complex topological superconducting networks for potential quantum computing applications.

Contribution

It introduces a novel 2D epitaxial S-Sm heterostructure with properties comparable to nanowire systems, facilitating scalable topological superconducting networks.

Findings

High-quality epitaxial Al on InAs/InGaAs heterostructure achieved

Demonstrated gateable Josephson junctions with high transparency

Established potential for complex topological superconductor networks

Abstract

Progress in the emergent field of topological superconductivity relies on synthesis of new material combinations, combining superconductivity, low density, and spin-orbit coupling (SOC). For example, theory [1-4] indicates that the interface between a one-dimensional (1D) semiconductor (Sm) with strong SOC and a superconductor (S) hosts Majorana modes with nontrivial topological properties [5-8]. Recently, epitaxial growth of Al on InAs nanowires was shown to yield a high quality S-Sm system with uniformly transparent interfaces [9] and a hard induced gap, indicted by strongly suppressed sub gap tunneling conductance [10]. Here we report the realization of a two-dimensional (2D) InAs/InGaAs heterostructure with epitaxial Al, yielding a planar S-Sm system with structural and transport characteristics as good as the epitaxial wires. The realization of 2D epitaxial S-Sm systems represent a significant advance over wires, allowing extended networks via top-down processing. Among numerous potential applications, this new material system can serve as a platform for complex networks of topological superconductors with gate-controlled Majorana zero modes [1-4]. We demonstrate gateable Josephson junctions and a highly transparent 2D S-Sm interface based on the product of excess current and normal state resistance.