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

TL;DR

This paper demonstrates high-fidelity single-shot readout of defect spins in silicon carbide, achieving coherence times over 5 seconds, which advances scalable quantum information processing in this material.

Contribution

It introduces a spin-to-charge conversion technique for single-shot readout in silicon carbide, enabling long coherence times and electrical readout possibilities.

Findings

Achieved over 80% readout fidelity without pre- or post-selection.

Measured spin coherence times exceeding 5 seconds.

Enabled scalable quantum node development with electrical readout potential.

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 post-selection, resulting in a high signal-to-noise ratio (SNR) 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 T2 > 5s, 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.