Neutral Silicon-Vacancy Center in Diamond - Spin Polarization and Lifetimes
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-08-31 |
| Journal | Physical Review Letters |
| Authors | Ben L. Green, Sinead Mottishaw, Ben G. Breeze, A. M. Edmonds, Ulrika F. S. DâHaenens-Johansson |
| Institutions | Australian National University, Element Six (United Kingdom) |
| Citations | 73 |
| Analysis | Full AI Review Included |
The Neutral Silicon-Vacancy Center (SiVâ°) in Diamond: Material Requirements for Long-Range Quantum Communication
Section titled âThe Neutral Silicon-Vacancy Center (SiVâ°) in Diamond: Material Requirements for Long-Range Quantum CommunicationâThis technical documentation analyzes the requirements and achievements detailed in the research paper on SiVâ° spin polarization and lifetimes, highlighting how 6CCVDâs advanced MPCVD diamond materials and customization services are essential for replicating and advancing this critical quantum research.
Executive Summary
Section titled âExecutive SummaryâThe study successfully demonstrates the optical spin polarization and exceptional spin lifetimes of the neutral silicon-vacancy (SiVâ°) defect in CVD diamond, positioning it as a highly promising platform for quantum communication technologies.
- Quantum Emitter Identified: SiVâ°, an S=1 defect, exhibits a primary Zero-Phonon Line (ZPL) at 946 nm (1.31 eV), suitable for integration with existing photonic systems.
- High Polarization: Achieved bulk spin polarization up to 5.2% at 10 K under 532 nm excitation, confirming efficient optical spin state initialization.
- Exceptional Lifetimes: Demonstrated a long spin coherence time (Tâ > 100 ”s at 27 K) and a spin relaxation limit (Tâ > 25 s at 15 K), significantly exceeding the performance of other SiV charge states.
- High Photonic Efficiency: The high Debye-Waller factor (â 0.8) ensures efficient coupling of the spin state to emitted photons.
- Telecoms Compatibility: SiVâ° emission falls within the 980 nm band, enabling downconversion to the critical 1550 nm telecoms wavelength for long-range quantum networks.
- Material Basis: The results rely on high-purity CVD diamond grown on specific crystallographic orientations ({100} and {113}), followed by precise electron irradiation and annealing for defect engineering.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the study, defining the performance metrics of the SiVâ° quantum system.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Defect Type | SiVâ° (Neutral Silicon-Vacancy) | N/A | S = 1 ground state |
| Zero-Phonon Line (ZPL) | 946 | nm | Primary optical transition (1.31 eV) |
| Maximum Bulk Spin Polarization (Ο) | 5.2 | % | Sample A, 10 K, 532 nm excitation |
| Spin Coherence Time (Tâ) | 103 | ”s | Measured at 27 K (limited by spin-spin interactions) |
| Spin Relaxation Limit (Tâ) | > 25 | s | Measured at 15 K (Sample B) |
| Room Temperature Tâ | 80 | ”s | Measured at 292 K (Sample B) |
| Zero-Field Splitting (ZFS, D) | +1000 | MHz | Measured at 300 K |
| ZPL Splitting (Observed) | 0.4 | nm | Equivalent to 134 GHz |
| Debye-Waller Factor | â 0.8 | N/A | High factor ensures efficient photon emission |
| Orbach Process Energy (ÎE) | 22 | meV | Matches observed phonon sideband |
Key Methodologies
Section titled âKey MethodologiesâThe successful creation and characterization of the SiVâ° centers required precise control over diamond growth, defect creation, and advanced spectroscopic techniques.
- Material Growth: Diamond samples were grown using Chemical Vapor Deposition (CVD), incorporating silane (SiH4) into the process gases to introduce silicon impurities.
- Substrate Orientation: Two distinct HPHT substrates were used to study orientational effects: {100}-oriented (Sample A) and {113}-oriented (Sample B).
- Defect Creation (Sample A):
- Irradiation: 2.0 MeV electrons at a dose of 5.4 x 1017 e-cm-2.
- Annealing: Sequential annealing for 4 hours each at 400 °C and 800 °C.
- Resulting Concentration: 5(2) ppb of SiVâ°.
- Defect Creation (Sample B):
- Irradiation: 1.5 MeV electrons at a dose of 1 x 1018 e-cm-2.
- Annealing: 4 hours at 900 °C.
- Resulting Concentration: 75(8) ppb of SiVâ°.
- Spectroscopy: Continuous Wave (CW) and pulsed Electron Paramagnetic Resonance (EPR) measurements were performed using a Bruker E580 spectrometer combined with optical excitation (532 nm, 830 nm, and tuneable 915-985 nm lasers).
- Lifetime Measurement: Tâ (longitudinal relaxation) was measured via echo-detected inversion-recovery. Tâ (coherence time) was measured via Hahn echo-decay sequences.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-purity, custom-engineered MPCVD diamond required to replicate and extend this SiVâ° research into scalable quantum devices.
Applicable Materials for SiVâ° Research
Section titled âApplicable Materials for SiVâ° ResearchâThe long spin lifetimes and high Debye-Waller factor of SiVâ° necessitate extremely low-strain, high-purity diamond material.
| Material Requirement | 6CCVD Solution | Technical Rationale |
|---|---|---|
| High Purity Substrates | Optical Grade Single Crystal Diamond (SCD) | Our SCD material offers extremely low nitrogen and metallic impurity levels, minimizing background noise and maximizing Tâ coherence times. |
| Silicon Incorporation | Custom Doped MPCVD Diamond | We offer precise control over gas mixtures, enabling the controlled introduction of silane during growth to achieve target Si concentrations (ppb to ppm range) for optimal SiV formation. |
| High-Quality Surfaces | SCD Polishing (Ra < 1 nm) | Low surface roughness is critical for minimizing surface-related decoherence and integrating photonic structures (e.g., waveguides or resonators) essential for quantum communication. |
Customization Potential for Quantum Defect Engineering
Section titled âCustomization Potential for Quantum Defect EngineeringâReplicating the SiVâ° results requires precise control over material geometry, orientation, and post-processing preparation. 6CCVD offers full customization to meet these demands:
- Custom Dimensions and Thickness: We supply SCD plates and wafers up to 125 mm in size, with thicknesses ranging from 0.1 ”m to 500 ”m, allowing researchers to optimize material volume for bulk measurements or thin films for integrated photonics.
- Crystallographic Orientation: The paper utilized {100} and {113} orientations. 6CCVD provides custom-oriented SCD substrates, ensuring the precise alignment necessary for strain engineering and maximizing the collection efficiency of specific defect orientations.
- Metalization Services: Future work, such as Optically Detected Magnetic Resonance (ODMR) mentioned in the paper, requires integrated microwave structures. 6CCVD offers in-house metalization capabilities, including Au, Pt, Pd, Ti, W, and Cu, deposited to custom patterns and thicknesses.
- Post-Processing Preparation: While 6CCVD does not perform irradiation, we provide high-purity, pre-polished SCD substrates optimized for subsequent high-energy electron irradiation and high-temperature annealing processes (up to 900 °C) used for SiVⰠcreation.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in MPCVD growth parameters and material science for quantum applications. We can assist researchers with:
- Material Selection: Consulting on the optimal starting material purity and orientation for SiVâ°, NVâ», or other color center projects.
- Defect Optimization: Advising on precursor gas ratios and growth conditions to achieve desired silicon incorporation levels for efficient defect creation.
- Integration Planning: Providing technical specifications and custom polishing to ensure compatibility with advanced fabrication techniques (e.g., etching, lithography) required for integrated quantum communication circuits.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We demonstrate optical spin polarization of the neutrally charged silicon-vacancy defect in diamond (SiV^{0}), an S=1 defect which emits with a zero-phonon line at 946 nm. The spin polarization is found to be most efficient under resonant excitation, but nonzero at below-resonant energies. We measure an ensemble spin coherence time T_{2}>100 ÎŒs at low-temperature, and a spin relaxation limit of T_{1}>25 s. Optical spin-state initialization around 946 nm allows independent initialization of SiV^{0} and NV^{-} within the same optically addressed volume, and SiV^{0} emits within the telecoms down-conversion band to 1550 nm: when combined with its high Debye-Waller factor, our initial results suggest that SiV^{0} is a promising candidate for a long-range quantum communication technology.