Gate-Tunable Transmon Using Selective-Area-Grown Superconductor-Semiconductor Hybrid Structures on Silicon

TL;DR

This paper introduces a gate-tunable transmon qubit using selectively grown superconductor-semiconductor hybrid structures on silicon, demonstrating high coherence and tunability for quantum computing applications.

Contribution

It presents a novel planar InAs nanowire-based gatemon on silicon with high-quality resonators and detailed coherence measurements, advancing scalable quantum hardware.

Findings

Achieved high internal quality factor of 2×10^5 in superconducting resonators.

Demonstrated coherent control with T1 ≈ 700 ns and T2* ≈ 20 ns.

Inferred high junction transparency of 0.4–0.9 from anharmonicity analysis.

Abstract

We present a gate-voltage tunable transmon qubit (gatemon) based on planar InAs nanowires that are selectively grown on a high resistivity silicon substrate using III-V buffer layers. We show that low loss superconducting resonators with an internal quality of $2\times 10^5$ can readily be realized using these substrates after the removal of buffer layers. We demonstrate coherent control and readout of a gatemon device with a relaxation time, $T_{1}\approx 700\,\mathrm{ns}$, and dephasing times, $T_2^{\ast}\approx 20\,\mathrm{ns}$ and $T_{\mathrm{2,echo}} \approx 1.3\,\mathrm{\mu s}$. Further, we infer a high junction transparency of $0.4 - 0.9$ from an analysis of the qubit anharmonicity.