Photoelectric detection of single spins in diamond by optically controlled discharge of long-lived trap states

TL;DR

This paper presents a novel electrical spin readout method using long-lived trap states in diamond, enabling stable, chip-scalable detection of single spins with potential advantages over optical techniques.

Contribution

Introduction of CCDMR, a new charge-based spin readout technique in diamond that leverages long-lived trap states for stable, electrical detection of single NV center spins.

Findings

Demonstrated spin-dependent charge trapping and release in diamond.

Achieved coherent control and readout of single NV spins via charge signals.

Identified charge trapping mechanisms relevant for spin detection.

Abstract

Electrical detection methods for solid-state spins are attractive for quantum technologies, being readily chip-scalable and not subject to the small photon budgets of single emitters. However, realising electrical spin readout in wide-bandgap materials with similar fidelity and bandwidth to optical approaches remains challenging. Here, we introduce a photoelectrical spin readout scheme that detects spin information stored long-term as trapped electrical charges. Using nitrogen-vacancy (NV) centres in diamond as a model system, spin-dependent photoionisation generates charge carriers that are stored in long-lived trap states at a diamond-metal Schottky junction. On-demand illumination of the junction under electrical bias releases stored charge, yielding a photocurrent transient proportional to the amount of trapped charge and hence spin state. Spin readout after coherent control of single NVs is demonstrated using charge readout in a protocol we call charge-capture detected magnetic resonance (CCDMR), and we use charge-based imaging to identify charge carrier generation and trapping processes. Our results establish CCDMR as a new technique for solid-state spin qubit readout, combining attaractive features of electrical detection with the stability of long-lived charge traps in wide-bandgap materials.