Optically Detected Magnetic Resonance in Neutral Silicon Vacancy Centers in Diamond via Bound Exciton States
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-11-30 |
| Journal | Physical Review Letters |
| Authors | Zi-Huai Zhang, Paul Stevenson, GergĆ Thiering, Brendon C. Rose, Ding Huang |
| Institutions | HUN-REN Wigner Research Centre for Physics, Princeton University |
| Citations | 53 |
| Analysis | Full AI Review Included |
Technical Documentation & Quantum Material Brief
Section titled âTechnical Documentation & Quantum Material BriefâOptically Detected Magnetic Resonance in Neutral Silicon Vacancy Centers (SiV$^{0}$)
Section titled âOptically Detected Magnetic Resonance in Neutral Silicon Vacancy Centers (SiV$^{0}$)âThis document analyzes the recent breakthrough in SiV$^{0}$ quantum control, highlighting the critical material specifications required for replication and advancement, and detailing how 6CCVDâs expertise in MPCVD diamond fabrication directly supports this cutting-edge research.
Executive Summary
Section titled âExecutive SummaryâThe research successfully demonstrates the first realization of Optically Detected Magnetic Resonance (ODMR) and coherent spin control in the neutral silicon vacancy (SiV$^{0}$) center in diamond, validating its potential as a superior quantum memory candidate compared to the Nitrogen Vacancy (NV) center.
| Parameter | Achievement | Implication for Quantum Technology |
|---|---|---|
| ODMR Mechanism | Enabled by efficient optical spin polarization via newly discovered higher-lying Bound Exciton (BE) states (825-890 nm). | Provides a robust, resonant initialization and readout scheme. |
| Spin Coherence (T2) | Measured at 55.5 ± 10.6 ”s at 6 K (Hahn echo sequence). | Confirms SiV$^{0}$âs long coherence time potential at low magnetic fields. |
| Spin Dephasing (T2*) | Measured at 202 ± 16 ns (Ramsey sequence). | Demonstrates high-quality spin manipulation capability. |
| Material Requirement | High-purity, isotopically enriched CVD diamond (e.g., $^{29}$Si doping, high SiV$^{0}$ concentration up to $4.0 \times 10^{16}$ cm-3). | Requires precise control over defect incorporation and isotopic purity (e.g., $^{12}$C). |
| Key Transitions | ODMR observed using BE excitation at 855.65 nm; ZPL emission at 946 nm. | Establishes critical optical wavelengths for SiV$^{0}$ spin-photon interface development. |
| Future Scope | The BE state control scheme is applicable to other emerging Group IV vacancy centers (e.g., SnV, GeV). | Broadens the utility of high-purity CVD diamond materials in solid-state quantum computing. |
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results, defining the performance metrics achieved for the SiV$^{0}$ quantum system.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Spin Coherence Time (T2) | 55.5 ± 10.6 | ”s | Measured at 6 K using Hahn echo sequence. |
| Spin Dephasing Time (T2*) | 202 ± 16 | ns | Measured at 6 K using Ramsey sequence. |
| Spin Relaxation Time (T1) | > 30 | ms | Measured at 6 K (No decay observed up to 30 ms). |
| Spin Relaxation Time (T1) | 1.38 ± 0.21 | ms | Measured at 50 K (Orbach process limited). |
| ODMR Central Frequency | 944 | MHz | Associated with $^{28}$Si and $^{30}$Si species. |
| ODMR Hyperfine Frequency | 912 | MHz | Associated with lower frequency $^{29}$Si hyperfine transition. |
| BE Excitation Wavelength | 855.65 | nm | Used for efficient ODMR observation. |
| ZPL Emission Wavelength | 946 | nm | Primary emission line detected for ODMR readout. |
| Inhomogeneous Linewidth | 1.47 ± 0.44 | MHz | Corresponds to T2* â 216 ± 64 ns. |
| SiV0 Concentration (D1) | $4.0 \times 10^{16}$ | cm-3 | CVD grown sample, high density. |
| Operating Temperature | 5.5 - 6 | K | Cryogenic environment for optimal coherence. |
Key Methodologies
Section titled âKey MethodologiesâThe successful observation of ODMR in SiV$^{0}$ relied on precise material engineering and advanced pulsed measurement techniques:
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Material Growth and Doping:
- Diamond samples (D1, D2) were grown via Chemical Vapor Deposition (CVD).
- Samples were doped during growth using isotopically enriched $^{29}$Si (90% enrichment).
- High-Pressure High-Temperature (HPHT) annealing was performed post-growth.
- Sample D3 was boron-doped CVD diamond implanted with $^{28}$Si.
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Optical and Microwave Setup:
- Measurements performed in a helium flow cryostat at low temperatures (5.5 K to 6 K).
- Excitation provided by narrow linewidth tunable CW Ti:Sapphire lasers (800 nm - 1000 nm range).
- Microwave (MW) excitation applied via a 70 ”m wire stretched across the sample, generated by amplified signal generators.
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Spectroscopy Techniques:
- Photoluminescence Excitation (PLE): Used to confirm the association of higher-lying transitions (825-890 nm) with the SiV$^{0}$ center by detecting ZPL emission at 946 nm.
- Optical Spin Polarization (OSP): Measured using a two-pulse Hahn echo sequence (200 ns $\pi$ pulse) after optical excitation, demonstrating up to 40%-60% bulk spin polarization.
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Coherent Control Sequences:
- Pulsed ODMR: Used for Rabi oscillation measurements (coherent control) and T1/T2 characterization.
- Ramsey Sequence: Used to measure spin dephasing time (T2*).
- Hahn Echo Sequence: Used to refocus coherence and measure spin coherence time (T2).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe realization of robust SiV$^{0}$ quantum systems demands ultra-high purity, low-strain diamond materials with precise defect engineering. 6CCVD is uniquely positioned to supply the foundational materials necessary to replicate and advance this research.
Applicable Materials for SiV$^{0}$ Quantum Research
Section titled âApplicable Materials for SiV$^{0}$ Quantum ResearchâTo achieve the long coherence times and high optical quality demonstrated in this paper, researchers require high-purity, low-strain Single Crystal Diamond (SCD).
| 6CCVD Material Solution | Specification & Relevance |
|---|---|
| Optical Grade SCD (Low Strain) | Essential for minimizing spectral diffusion and achieving narrow ZPL linewidths, critical for high-fidelity spin-photon interfaces. |
| Isotopically Purified SCD | Growth of diamond wafers with >99.999% $^{12}$C purity to suppress decoherence caused by the naturally abundant $^{13}$C nuclear spin bath. This is crucial for extending T2 beyond the reported 55.5 ”s limit. |
| Custom Silicon Doping | Precise incorporation of Silicon (Si) during MPCVD growth to control SiV$^{0}$ concentration (up to $10^{17}$ cm-3 range) for ensemble or single-defect studies. |
| Substrates for Implantation | Ultra-low defect SCD substrates (up to 10 mm thick) suitable for post-growth ion implantation (e.g., $^{28}$Si or $^{29}$Si) to create shallow SiV$^{0}$ layers for integrated quantum devices. |
Customization Potential for Advanced Devices
Section titled âCustomization Potential for Advanced DevicesâThe experimental setup utilized specific sample geometries and required precise microwave delivery, areas where 6CCVDâs fabrication capabilities provide immediate value:
- Custom Dimensions and Thickness: 6CCVD supplies SCD plates up to 500 ”m thick and substrates up to 10 mm. We can provide the exact 0.66 mm thickness used in the absorption measurements, or custom wafers up to 125 mm (PCD) for large-scale integration.
- Ultra-Low Roughness Polishing: Quantum experiments are highly sensitive to surface quality. We guarantee Ra < 1 nm polishing on SCD wafers, ensuring minimal optical scattering and strain at the surface, which is vital for coupling SiV$^{0}$ centers to nanophotonic structures.
- Integrated Metalization Services: For on-chip microwave delivery (e.g., striplines or coplanar waveguides required for pulsed ODMR/ESR), 6CCVD offers in-house deposition of standard metals including Au, Pt, Ti, W, and Cu with high precision patterning.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and quantum engineers specializes in defect creation and characterization. We offer consultation services to assist researchers in:
- Optimizing SiV$^{0}$ concentration and depth profiles for specific applications (e.g., bulk coherence vs. near-surface coupling).
- Selecting the optimal isotopic purity ($^{12}$C, $^{29}$Si) to maximize T2 and control hyperfine interactions.
- Designing custom diamond geometries and metalization layers for integrated ODMR/ESR quantum circuits.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We offer global shipping (DDU default, DDP available) to ensure rapid delivery of mission-critical quantum materials.
View Original Abstract
Neutral silicon vacancy (SiV^{0}) centers in diamond are promising candidates for quantum networks because of their excellent optical properties and long spin coherence times. However, spin-dependent fluorescence in such defects has been elusive due to poor understanding of the excited state fine structure and limited off-resonant spin polarization. Here we report the realization of optically detected magnetic resonance and coherent control of SiV^{0} centers at cryogenic temperatures, enabled by efficient optical spin polarization via previously unreported higher-lying excited states. We assign these states as bound exciton states using group theory and density functional theory. These bound exciton states enable new control schemes for SiV^{0} as well as other emerging defect systems.