Transforming Native Oxide into a Metallic Platinum--Niobium Alloy for Passivation of Superconducting Niobium Films
Abstract
Dielectric losses at surfaces and interfaces remains a primary limitation to coherence in superconducting transmon qubits. Niobium (Nb), a widely used material in superconducting quantum circuits, readily forms native oxides under ambient conditions, leading to lossy dielectric interfaces that degrade device performance. Here, we demonstrate a novel fabrication strategy that chemically transforms the native dielectric oxide on Nb into a metallic Pt--Nb surface alloy through post-oxidation Pt deposition followed by thermal annealing, thereby stabilizing Nb surfaces against further oxidation, potentially including sidewall regions. High-purity Nb films were fabricated with bulk-like superconducting transition temperatures (Tc = 9.30±0.10~K). Spectroscopic and microscopic analyses confirm the conversion of the native oxide into a chemically stable, metallic alloy-dominated layer that suppresses subsequent oxide growth. Ab initio simulations elucidate the atomic-scale rearrangement and electronic structure evolution associated with Pt incorporation into native niobium oxide, providing insight into the mechanism underlying the oxide-to-metal transformation and stabilization of the alloyed surface.
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BibTeX
@misc{chattaraj2026transforming,
title = {{Transforming Native Oxide into a Metallic Platinum--Niobium Alloy for Passivation of Superconducting Niobium Films}},
author = {Ananya Chattaraj and Conan Weiland and Bruce Ravel and Kim Kisslinger and Sooyeon Hwang and Xiao Tong and Ajith Pattammattel and Andrew M. Kiss and Steven L. Hulbert and Aswin kumar Anbalagan and Andrew L. Walter and Peter V. Sushko and Mingzhao Liu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.00429},
eprint = {2607.00429},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.00429},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Transforming Native Oxide into a Metallic Platinum--Niobium Alloy for Passivation of Superconducting Niobium Films
AU - Ananya Chattaraj
AU - Conan Weiland
AU - Bruce Ravel
AU - Kim Kisslinger
AU - Sooyeon Hwang
AU - Xiao Tong
AU - Ajith Pattammattel
AU - Andrew M. Kiss
AU - Steven L. Hulbert
AU - Aswin kumar Anbalagan
AU - Andrew L. Walter
AU - Peter V. Sushko
AU - Mingzhao Liu
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2607.00429
UR - https://arxiv.org/abs/2607.00429
AB - Dielectric losses at surfaces and interfaces remains a primary limitation to coherence in superconducting transmon qubits. Niobium (Nb), a widely used material in superconducting quantum circuits, readily forms native oxides under ambient conditions, leading to lossy dielectric interfaces that degrade device performance. Here, we demonstrate a novel fabrication strategy that chemically transforms the native dielectric oxide on Nb into a metallic Pt--Nb surface alloy through post-oxidation Pt deposition followed by thermal annealing, thereby stabilizing Nb surfaces against further oxidation, potentially including sidewall regions. High-purity Nb films were fabricated with bulk-like superconducting transition temperatures (T_c = 9.30±0.10~K). Spectroscopic and microscopic analyses confirm the conversion of the native oxide into a chemically stable, metallic alloy-dominated layer that suppresses subsequent oxide growth. Ab initio simulations elucidate the atomic-scale rearrangement and electronic structure evolution associated with Pt incorporation into native niobium oxide, providing insight into the mechanism underlying the oxide-to-metal transformation and stabilization of the alloyed surface.
ER -