Performance of high impedance resonators in dirty dielectric environments

TL;DR

This study evaluates high-impedance NbTiN resonators near common oxides used in spin qubit fabrication, demonstrating their robustness and suitability for integration into spin-based quantum processors despite some loss mechanisms.

Contribution

It provides the first comprehensive analysis of NbTiN resonator performance in typical oxide environments relevant for spin qubits, showing their potential for scalable quantum computing.

Findings

Internal quality factors exceed 10^3 in all oxide configurations.

Losses are mainly due to coupling with two-level systems in oxides.

Resonator performance remains robust in magnetic fields and elevated temperatures.

Abstract

High-impedance resonators are a promising contender for realizing long-distance entangling gates between spin qubits. Often, the fabrication of spin qubits relies on the use of gate dielectrics which are detrimental to the quality of the resonator. Here, we investigate loss mechanisms of high-impedance NbTiN resonators in the vicinity of thermally grown SiO\textsubscript{2} and Al\textsubscript{2}O\textsubscript{3} fabricated by atomic layer deposition. We benchmark the resonator performance in elevated magnetic fields and at elevated temperatures and find that the internal quality factors are limited by the coupling between the resonator and two-level systems of the employed oxides. Nonetheless, the internal quality factors of high-impedance resonators exceed $10^3$ in all investigated oxide configurations which implies that the dielectric configuration would not limit the performance of resonators integrated in a spin-qubit device. Because these oxides are commonly used for spin qubit device fabrication, our results allow for straightforward integration of high-impedance resonators into spin-based quantum processors. Hence, these experiments pave the way for large-scale, spin-based quantum computers.