Vanadium in Silicon Carbide: Telecom-ready spin centres with long relaxation lifetimes and hyperfine-resolved optical transitions

TL;DR

This paper investigates vanadium defects in silicon carbide, revealing their long spin relaxation times, stable charge states, and hyperfine structures, highlighting their potential for telecom-compatible quantum technologies.

Contribution

It provides the first detailed measurements of T1, charge dynamics, and hyperfine structure of vanadium in SiC, advancing their application in quantum communication.

Findings

Spin relaxation time up to 25s at 100mK

High spin contrast exceeding 90%

Hyperfine-resolved optical transitions

Abstract

Vanadium in silicon carbide (SiC) is emerging as an important candidate system for quantum technology due to its optical transitions in the telecom wavelength range. However, several key characteristics of this defect family including their spin relaxation lifetime (T1), charge state dynamics, and level structure are not fully understood. In this work, we determine the T1 of an ensemble of vanadium defects, demonstrating that it can be greatly enhanced at low temperature. We observe a large spin contrast exceeding 90% and long spin-relaxation times of up to 25s at 100mK, and of order 1s at 1.3K. These measurements are complemented by a characterization of the ensemble charge state dynamics. The stable electron spin furthermore enables high-resolution characterization of the systems' hyperfine level structure via two-photon magneto-spectroscopy. The acquired insights point towards high-performance spin-photon interfaces based on vanadium in SiC.