Potential Spin Qubits Using Transition-Metal-Ion Doped Halide Double Perovskites

Yuttapoom puttisong^a, Sakarn Khamkaeo^a, Kunpot Mopoung^a, Kingshuk Murati^b, Maarten De Dreu^b, Anna Dávid^a, Muyi Zhang^a, Mats Fahlman^a, Feng Gao^a, Peter C.M. Chirtianen^a, Irina A. Buyanova^a, Weimin M. Chen^a

^aLinköping university, Olaus Magnus väg, Linköping, Sweden

^bHigh Field Magnet Laboratory, HFML-EMFL, Radboud University, The Netherlands

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Oral, Yuttapoom puttisong, presentation 109
Publication date: 11th March 2026

Solid-state spin qubits are a cornerstone of scalable quantum networks, traditionally requiring nuclear-spin-free hosts to maintain coherence. In this work, we present the first demonstration of halide double perovskites (HDPs) as a viable platform for solid-state spin qubits, establishing a new material library for quantum information technology. Utilizing transition-metal (TM) centers—Cr³⁺ and Fe³⁺ ions—doped into a Cs₂In(Na,Ag)Cl₆ host¹, we demonstrate that these centers exhibit long-lived electron spin coherence despite the nuclear-spin-rich environment of the perovskite lattice. We report benchmark coherence times T_₂ of 29.5 µs for Cr³⁺ and 21.2 µs for Fe³⁺ at 4 K. Our findings reveal that strong spin localization at the TM sites facilitates deterministic electron-nuclear (e-N) spin rotations with neighboring ^35,37Cl and ¹³³Cs nuclear spins, limiting the number of e-N interaction and resulting in long spin coherrence in the nuclear spin-rich hosts. Furthermore, we show that Cr³⁺ centers are optically addressable through spin-selective intra-d-shell transitions, enabling clear protocols for high-fidelity optical initialization and readout. These results highlight the potential of halide perovskites to provide a chemically tunable "sandbox" for engineering advanced quantum states, such as qudits, using inexpensive and scalable solution-based synthesis. By combining superior optoelectronic properties with robust spin coherence, this platform opens new avenues for integrating quantum nodes with existing semiconductor technologies.

References:

[1] 1. Khamkaeo, S. et al. Spin Qubits Candidate in Transition-Metal-Ion doped Halide Double Perovskites. Nat Commun 17, 415 (2026).

Acknowledgements:

This work was financially supported by the Swedish Research Council (Dnr. 2021-05790), the Knut and Alice Wallenberg Foundation (Dnr. KAW 2019.0082), the Swedish Energy Agency (Dnr. 48758-1 and Dnr. 48594-1), and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). The measurements in high magnetic fields were supported by HFML-FELIX, member of the European Magnetic Field Laboratory (EMFL) and the EU Horizon 2020 EMFL-ISABEL secondment program.

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