Group publications 2
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Nature Communications 17, 377 (2026)
@article{zhou_observation_2026, title = {Observation of interface piezoelectricity in superconducting devices on silicon}, volume = {17}, url = {https://doi.org/10.1038/s41467-025-67066-z}, doi = {10.1038/s41467-025-67066-z}, journal = {Nature Communications}, pages = {377}, author = {Zhou, H. and Li, E. and Godeneli, K. and Zhang, Z.-H. and Jahanbani, S. and Yu, K. and Odeh, M. and Aloni, S. and Griffin, S. and Sipahigil, A.}, year = {2026}, arxiv = {2409.10626} }The development of superconducting quantum processors relies on understanding and mitigating decoherence in superconducting qubits. Piezoelectric coupling contributes to decoherence by mediating energy exchange between microwave photons and acoustic phonons. Although bulk centrosymmetric materials like silicon and sapphire are non-piezoelectric and commonly used as qubit substrates, the lack of centrosymmetry at interfaces may induce piezoelectric losses. This effect was predicted decades ago but never experimentally observed in superconducting devices. Here, we report interface piezoelectricity at aluminum-silicon junctions and demonstrate it as a significant loss channel in superconducting devices. Using aluminum interdigital transducers on silicon, we observe piezoelectric transduction from room to millikelvin temperatures, with an effective electromechanical coupling factor K 2 ≈ (3 ± 0.4) × 10 −5 %, comparable to weakly piezoelectric substrates. Modeling shows this mechanism limits qubit quality factors to Q 10 4 − 10 8 , depending on surface participation and mode matching. These findings reveal interface piezoelectricity as a major dissipation channel and highlight the need for heterostructure and phononic engineering in next-generation superconducting qubits.
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Nature Physics 21, 406–411 (2025)
@article{odeh_non-markovian_2025, title = {Non-{Markovian} dynamics of a superconducting qubit in a phononic bandgap}, volume = {21}, url = {https://www.nature.com/articles/s41567-024-02740-5}, doi = {10.1038/s41567-024-02740-5}, journal = {Nature Physics}, number = {3}, pages = {406--411}, issn = {1745-2473, 1745-2481}, author = {Odeh, Mutasem and Godeneli, Kadircan and Li, Eric and Tangirala, Rohin and Zhou, Haoxin and Zhang, Xueyue and Zhang, Zi-Huai and Sipahigil, Alp}, month = mar, year = {2025}, arxiv = {2312.01031} }The overhead to construct a logical qubit from physical qubits rapidly increases with the decoherence rate. Current superconducting qubits reduce dissipation due to two-level systems (TLSs) by using large device footprints. However, this approach provides partial protection, and results in a trade-off between qubit footprint and dissipation. This work introduces a new platform using phononics to engineer superconducting qubit-TLS interactions. We realize a superconducting qubit on a phononic bandgap metamaterial that suppresses TLS-mediated phonon emission. We use the qubit to probe its thermalization dynamics with the phonon-engineered TLS bath. Inside the phononic bandgap, we observe the emergence of non-Markovian qubit dynamics due to the Purcell-engineered TLS lifetime of 34 μs. We discuss the implications of these observations for extending qubit relaxation times through simultaneous phonon protection and miniaturization.