# Quantum transport in high-quality shallow InSb quantum wells

## TL;DR

This paper reports on the growth and characterization of high-quality InSb quantum wells with ultra-thin barriers, demonstrating high electron mobility and tunable carrier densities, advancing the development of topological quantum devices.

## Contribution

It introduces a novel heterostructure with ultra-thin barriers that achieves high mobility and tunability in InSb quantum wells, suitable for topological quantum applications.

## Key findings

- Electron mobility up to 350,000 cm²/(V·s)
- Gate-tunable carrier densities
- Effective mass of 0.02 m₀ and compatible Zeeman splitting

## Abstract

InSb is one of the promising candidates to realize a topological state through proximity induced superconductivity in a material with strong spin-orbit interactions. In two-dimensional systems, thin barriers are needed to allow strong coupling between superconductors and semiconductors. However, it is still challenging to obtain a high-quality InSb two-dimensional electron gas in quantum wells close to the surface. Here we report on a molecular beam epitaxy grown heterostructure of InSb quantum wells with substrate-side Si-doping and ultra-thin InAlSb (5 nm, 25 nm, and 50 nm) barriers to the surface. We demonstrate that the carrier densities in these quantum wells are gate-tunable and electron mobilities up to 350,000 $\rm{cm^2(Vs)^{-1}}$ are extracted from magneto-transport measurements. Furthermore, from temperature-dependent magneto-resistance measurements, we extract an effective mass of 0.02 $m_0$ and find a Zeeman splitting compatible with the expected g-factor.