TLS loss in superconducting resonators on epitaxial hBN thin films

Authors:J. Christiansen-Salameh, D.J. Temples, R. Linehan, S. Sussman, Aloyse Maille, F. Abouzahr, L. Alexis, K. Anyang, D. Bowring, G. Bratrud, E. Celi, A.H. Colón Cesaní, R. Khatiwada, D. Molenaar, O. Peek, A. Rodriguez, O. Seidel, D. Schlom, D. Sotir, S. Uemura, Y. Wu, E. Figueroa-Feliciano, D. Baxter, Z. Tian

Abstract:The integration of low-loss dielectrics into superconducting circuits is of importance to the functionality of quantum computers and sensors. In this work, we fabricate and measure niobium resonators atop few-layer, epitaxial hexagonal boron nitride (hBN) grown by Molecular Beam Epitaxy on a sapphire substrate and compare against a control counterpart without hBN. We conduct radiofrequency measurements which probe the responses to power, temperature, and temporal fluctuations of two-level systems. The resonators integrating hBN maintain low dielectric loss with a low-power internal loss tangent on the order of $10^{-6}$, and demonstrate hBN can be added to the conventional superconducting qubit stack with minimal degradation of the quality factor. This research represents a first step towards a materials-driven strategy to eliminate phonon-mediated correlated errors in solid-state quantum systems, which leverages the thermal properties of 2D materials to prevent athermal phonons excited in the device substrate from transmitting across the superconductor-substrate interface. The same technique applied to quantum sensors would maximize phonon collection by blocking phonons from entering passive metal films.

arXiv:2610.12556 [quant-ph]

(or arXiv:2610.12556v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2610.12556 arXiv-issued DOI via DataCite (pending registration)