# Spin Qubits Candidate in Transition-Metal-Ion doped Halide Double Perovskites

## TL;DR

Transition metal ions in halide double perovskites show promise as spin qubits with long coherence times and potential for quantum memory applications.

## Contribution

Transition metal ions in halide double perovskites are proposed as new candidates for spin qubits with long coherence and controllable nuclear spins.

## Key findings

- Cr3+ and Fe3+ ions in halide double perovskites exhibit long electron spin coherence times (T2 = 29.5 µs and 21.2 µs at 4 K).
- Spin localization enables electron-nuclear spin rotations with neighboring 35,37Cl and 133Cs nuclei.
- Optical transitions of Cr3+ spin centers are spin-selective, enabling optical addressing of spins.

## Abstract

Solid-state spin qubits offer a promising route toward scalable quantum technologies. Here we demonstrate that, despites of a nuclear-spin-rich host of halide double perovskites (HDPs), transition-metal centers (Cr3+ and Fe3+ ions) are a good candidate for spin qubits exhibiting long-lived electron spin coherence with \documentclass[12pt]{minimal}
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\begin{document}$${T}_{2}$$\end{document}T2 = 29.5 µs and 21.2 µs at 4 K, respectively. Notably, spin localization facilitates a well-defined electron-nuclear (e-N) spin rotation between the electron spin and the neighboring nuclear spins of 35,37Cl and133Cs. The resulting e-N spin cluster is readily beneficial for a target nuclear-spin sensing. For the Cr3+ spin centers, the optical transitions associated with Cr3+ spin centers is spin-selective thereby paving a way for optical addressing of spins. Our findings from these spin ensemble studies establish HDPs as a new promising platform for creating solid-state spin qubits using simple and inexpensive solution-based single crystal growth methods, broadening material applications of halide perovskites.

Systems of electron spins in nuclear-spin-rich hosts are gaining attention for quantum memory applications. Using spin ensemble studies, the authors propose transition metal ions in halide double perovskites as promising candidates, featuring long electron spin coherence and deterministic nuclear spin control.