Vanadium spin qubits as telecom quantum emitters in silicon carbide

Abstract

Solid-state quantum emitters with spin registers are promising platforms for quantum communication, yet few emit in the narrow telecom band necessary for low-loss fiber networks. Here, we create and isolate near-surface single vanadium dopants in silicon carbide (SiC) with stable and narrow emission in the O band, with brightness allowing cavity-free detection in a wafer-scale material. In vanadium ensembles, we characterize the complex d1 orbital physics in all five available sites in 4H-SiC and 6H-SiC. The optical transitions are sensitive to mass shifts from local silicon and carbon isotopes, enabling optically resolved nuclear spin registers. Optically detected magnetic resonance in the ground and excited orbital states reveals a variety of hyperfine interactions with the vanadium nuclear spin and clock transitions for quantum memories. Last, we demonstrate coherent quantum control of the spin state. These results provide a path for telecom emitters in the solid state for quantum applications.

Bottom‐Up Synthesis of Hexagonal Boron Nitride Nanoparticles with Intensity‐Stabilized Quantum Emitters

“…The quantum emitters in our study display very high brightness, with the majority of them exhibiting more than 500 kcounts s −1 at 2.5 mW of 532‐nm excitation, with a numerical aperture of 0.9. These count rates are comparable or higher than those of most emitters found in diamond, [ 14,28 ] silicon carbide, [ 43,44 ] rare‐earth material, [ 45 ] and carbon nanotubes. [ 46 ]…”

Identifying candidate hosts for quantum defects via data mining

“…These defects have been extensively explored in the context of solid-state laser development, in materials where extremely high doping concentrations are possible. However, exploring single defects as qubits is a more recent development 21,22 , partially facilitated by integration with nano-photonic circuits to modify and enhance their luminescence 23,24 . Although significant attention has thus far been paid to a handful of materials and defects, they represent only a small fraction of the greater body of potential defect-host systems.…”

Extrinsic Absorption Pathways in Vanadium‐Doped SiC Measured Using a Total Internal Reflection Geometry

“…The understanding of optical transitions mechanism is key for a variety of applications including photodetectors, [ 1,2 ] photovoltaics, [ 3,4 ] photoconductive semiconductor switches (PCSSs), [ 5–9 ] and quantum emitters. [ 10,11 ] Extrinsic excitation of defect levels with sub‐bandgap light is important when homogeneous photogeneration is required in bulk devices. Quantitative evaluation of this process using a simple absorption spectrum is complicated due to the interference with several other absorption mechanisms such as free carrier absorption, absorption between impurity levels, or intradopant optical absorption.…”

“…It has also received recent attention as a solid‐state quantum emitter at telecom wavelengths. [ 10,11 ] This is due to absorption and re‐emission of the V itself, with the SiC acting as a host matrix. Efficient pumping and emission from this level require knowledge of the other transition pathways present in SiC:V. SiC:V is typically grown using the Lely process and is used as a substrate for the growth of both SiC and GaN devices.…”