Symmetry-mediated quantum coherence of W5+ spins in an oxygen-deficient double perovskite

Abstract Elucidating the factors limiting quantum coherence in real materials is essential to the development of quantum technologies. Here we report a strategic approach to determine the effect of lattice dynamics on spin coherence lifetimes using oxygen deficient double perovskites as host materia...

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Main Authors: Shannon Bernier, Mekhola Sinha, Tyler J. Pearson, Peter V. Sushko, Paul H. Oyala, Maxime A. Siegler, W. Adam Phelan, Abby N. Neill, Danna E. Freedman, Tyrel M. McQueen
Format: Article
Language:English
Published: Nature Portfolio 2025-06-01
Series:npj Quantum Materials
Online Access:https://doi.org/10.1038/s41535-025-00782-3
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Summary:Abstract Elucidating the factors limiting quantum coherence in real materials is essential to the development of quantum technologies. Here we report a strategic approach to determine the effect of lattice dynamics on spin coherence lifetimes using oxygen deficient double perovskites as host materials. In addition to obtaining millisecond T 1 spin-lattice lifetimes at T ~ 10 K, measurable quantum superpositions were observed up to room temperature. We determine that T 2 enhancement in Sr2CaWO6-δ over previously studied Ba2CaWO6-δ is caused by a dynamically-driven increase in effective site symmetry around the dominant paramagnetic site, assigned as W5+ via electron paramagnetic resonance spectroscopy. Further, a combination of experimental and computational techniques enabled quantification of the relative strength of spin-phonon coupling of each phonon mode. This analysis demonstrates the effect of thermodynamics and site symmetry on the spin lifetimes of W5+ paramagnetic defects, an important step in the process of reducing decoherence to produce longer-lived qubits.
ISSN:2397-4648