Five-second coherence of a single spin with single-shot readout in silicon carbide.

Anderson, Christopher P; Glen, Elena O; Zeledon, Cyrus; Bourassa, Alexandre; Jin, Yu; Zhu, Yizhi; Vorwerk, Christian; Crook, Alexander L et al. · Sci Adv · 2022

basic_science · Level V

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Abstract

An outstanding hurdle for defect spin qubits in silicon carbide (SiC) is single-shot readout, a deterministic measurement of the quantum state. Here, we demonstrate single-shot readout of single defects in SiC via spin-to-charge conversion, whereby the defect's spin state is mapped onto a long-lived charge state. With this technique, we achieve over 80% readout fidelity without pre- or postselection, resulting in a high signal-to-noise ratio that enables us to measure long spin coherence times. Combined with pulsed dynamical decoupling sequences in an isotopically purified host material, we report single-spin <i>T</i><sub>2</sub> > 5 seconds, over two orders of magnitude greater than previously reported in this system. The mapping of these coherent spin states onto single charges unlocks both single-shot readout for scalable quantum nodes and opportunities for electrical readout via integration with semiconductor devices.