Few-Electron Single and Double Quantum Dots in an In As Two-Dimensional Electron Gas

Abstract

Most proof-of-principle experiments for spin qubits have been performed with GaAs-based quantum dots because of the excellent control they offer over tunneling barriers and the orbital and spin degrees of freedom. Here we present the first realization of high-quality single and double quantum dots hosted in an InAs two-dimensional electron gas, demonstrating accurate control down to the few-electron regime, where we observe a clear Kondo effect and singlet-triplet spin blockade. We measure an electronic g factor of 16 and a typical magnitude of the random hyperfine fields on the quantum dots of approximately 0.6mT. We estimate the spin-orbit length in the system to be approximately 5−10μm (which is almost 2 orders of magnitude longer than typically measured in InAs nanostructures), achieved by a very symmetric design of the quantum well. These favorable properties put the InAs two-dimensional electron gas on the map as a compelling host for studying fundamental aspects of spin qubits. Furthermore, having weak spin-orbit coupling in a material with a large Rashba coefficient potentially opens up avenues for engineering structures with spin-orbit coupling that can be controlled locally in space and/or time.