Sensitive detection of level anticrossing spectra of nitrogen vacancy centers in diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-09-21 |
| Journal | Physical review. B./Physical review. B |
| Authors | S. V. Anishchik, Konstantin L. Ivanov |
| Institutions | Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences |
| Citations | 18 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Sensitive Detection of Level Anti-Crossing Spectra in Diamond
Section titled âTechnical Documentation & Analysis: Sensitive Detection of Level Anti-Crossing Spectra in DiamondâThis document analyzes the research paper âSensitive detection of level anti-crossing spectra of nitrogen-vacancy centers in diamondâ to provide technical specifications and align the experimental requirements with the advanced MPCVD diamond solutions offered by 6ccvd.com.
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a highly sensitive method for probing the spin dynamics of negatively charged Nitrogen-Vacancy (NV-) centers in single crystal diamond using Level Anti-Crossing (LAC) spectroscopy coupled with lock-in detection.
- Core Achievement: Achieved a substantial increase (approximately two orders of magnitude) in LAC-line amplitude by optimizing the magnetic field modulation frequency ($f_m$).
- Methodology: Utilized low-amplitude magnetic field modulation ($B_m = 0.5$ G) and lock-in detection, varying $f_m$ from 12.5 kHz down to 17 Hz.
- Key Finding: The strong dependence of LAC-line amplitude on low modulation frequencies is attributed to slow dynamic processes, specifically long electronic T1-relaxation and nuclear spin relaxation times.
- Material Requirement: High-quality synthetic single crystal diamond (HPHT grown) was required, subsequently irradiated (3 MeV) and annealed (800° C) to achieve a high NV concentration (9.3 x 1017 cm-3).
- Application Relevance: The enhanced sensitivity allows for the detection of weak satellite LAC-lines, enabling the indirect detection and identification of low-concentration, otherwise âinvisibleâ paramagnetic defect centers (e.g., P1 centers).
- 6CCVD Value Proposition: 6CCVD supplies the high-purity, low-strain MPCVD Single Crystal Diamond (SCD) necessary to replicate and advance this quantum sensing research, offering superior control over nitrogen incorporation and surface quality (Ra < 1 nm).
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental section of the paper:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Base Material | Synthetic Diamond | N/A | HPHT grown, Single Crystal |
| NV- Concentration | 9.3 x 1017 | cm-3 | Average concentration after processing |
| Electron Irradiation Energy | 3 | MeV | Used for vacancy creation |
| Electron Irradiation Dose | 1018 | el/cm2 | Used for NV creation |
| Annealing Temperature | 800 | °C | 2 hours in vacuum |
| Excitation Wavelength | 532 | nm | Laser light source |
| Irradiation Power | 400 | mW | Used for photoluminescence |
| Modulation Frequency ($f_m$) Range | 17 to 12.5 | Hz to kHz | Experimental range tested |
| Modulation Amplitude ($B_m$) | 0.5 | G | Used for key LAC spectra figures |
| LAC Line Amplitude Increase | ~2 | Orders of Magnitude | Upon decreasing $f_m$ |
| Key LAC Magnetic Field ($B_0$) | 1024 | G | NV- ground state LAC |
| Satellite LAC Fields Detected | 0, 500, 590, 1007, 1037 | G | Lines originating from defect interactions |
Key Methodologies
Section titled âKey MethodologiesâThe experimental procedure focused on creating high-density NV centers and optimizing the lock-in detection parameters for maximum sensitivity to slow spin dynamics.
- Material Precursor: Single crystals of synthetic diamond (HPHT) were selected for high-temperature/high-pressure growth.
- Vacancy Creation: Samples were irradiated using fast electrons (3 MeV) at a high dose (1018 el/cm2).
- NV Center Formation: Samples were annealed in vacuum at 800° C for two hours, resulting in an average NV concentration of 9.3 x 1017 cm-3.
- Magnetic Field Alignment: The diamond crystal was precisely oriented such that the external magnetic field ($B_0$) was parallel to the [111] crystal axis (precision better than 0.1°).
- Field Modulation: A permanent magnetic field ($B_0$) was superimposed with a weak oscillating field ($B_m \cos(2\pi f_m t)$).
- Optical Setup: 532 nm laser light (400 mW) was used for excitation. The beam direction and the electric field vector ($\mathbf{E}$) were both perpendicular to the magnetic field vector ($B_0$).
- Signal Acquisition: Photoluminescence intensity was measured by a photo-multiplier and processed using a lock-in detector, with the modulation frequency ($f_m$) varied between 17 Hz and 12.5 kHz.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe sensitive detection of NV- LAC spectra requires diamond materials with exceptional purity, precise crystallographic orientation, and controlled defect concentration. 6CCVDâs MPCVD capabilities are ideally suited to meet and exceed these requirements for advanced quantum research.
Applicable Materials
Section titled âApplicable MaterialsâThe paper utilized HPHT diamond, but modern quantum experiments benefit significantly from the purity and strain control of MPCVD diamond.
| 6CCVD Material Recommendation | Description & Application |
|---|---|
| Optical Grade SCD | Ideal for quantum sensing and magnetometry. Offers ultra-low strain and minimal native defects, crucial for maximizing T2 coherence times, especially for low-concentration NV studies. |
| High-Nitrogen SCD Precursors | For replicating the high NV concentration (9.3 x 1017 cm-3) used in this study, 6CCVD can supply SCD wafers grown with controlled nitrogen incorporation, optimized for subsequent high-dose electron irradiation and 800° C annealing. |
| High-Purity SCD Wafers | Suitable for researchers who prefer to introduce nitrogen and vacancies via ion implantation or irradiation post-growth, ensuring maximum control over the final defect profile. |
Customization Potential
Section titled âCustomization Potentialâ6CCVD provides comprehensive material engineering services essential for advanced LAC spectroscopy and quantum device fabrication.
| Requirement from Research / Future Need | 6CCVD Capability |
|---|---|
| Precise Orientation & Strain | SCD wafers are available with precise crystallographic orientation (e.g., [111] axis alignment) and guaranteed low internal strain, critical for sharp LAC-lines. |
| Surface Quality | Ultra-low surface roughness polishing (Ra < 1 nm for SCD) minimizes surface-related decoherence and scattering losses, enhancing signal-to-noise ratio in PL detection. |
| Custom Dimensions | We offer custom dimensions and thicknesses for SCD (0.1 ”m to 500 ”m) and large-area PCD (up to 125 mm), allowing researchers to tailor substrates to specific magnetometry setups. |
| Metalization for Integration | For future integrated quantum devices requiring electrodes (e.g., for electric field control), 6CCVD offers in-house metalization services including Au, Pt, Pd, Ti, W, and Cu deposition. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team can assist researchers in optimizing the material selection and processing recipe for Level Anti-Crossing (LAC) Spectroscopy projects. We provide consultation on:
- Nitrogen Control: Tailoring MPCVD growth parameters to achieve the specific nitrogen concentration required for target NV- densities (e.g., matching the 9.3 x 1017 cm-3 used here).
- Post-Processing Optimization: Advising on the optimal thickness and purity of SCD substrates to maximize the yield and uniformity of NV centers following high-energy irradiation (3 MeV) and annealing (800° C).
- Material Selection: Ensuring the chosen diamond grade provides the necessary T1 and T2 relaxation characteristics required to exploit the low-frequency modulation effects demonstrated in this paper.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We report a study of the magnetic field dependence of photoluminescence of NV$^-$ centers (negatively charged nitrogen-vacancy centers) in diamond single crystals. In such a magnetic field dependence characteristic sharp features are observed, which are coming from Level Anti-Crossings (LACs) in a coupled electron-nuclear spin system. For sensitive detection of such LAC-lines we use lock-in detection to measure the photoluminescence intensity. This experimental technique allows us to obtain new LAC lines. Additionally, a remarkably strong dependence of the LAC-lines on the modulation frequency is found. Specifically, upon decrease of the modulation frequency from 12 kHz to 17 Hz the amplitude of the LAC-lines increases by approximately two orders of magnitude. To take a quantitative account for such effects, we present a theoretical model, which describes the spin dynamics in a coupled electron-nuclear spin system under the action of an oscillating external magnetic field. Good agreement between experiments and theory allows us to conclude that the observed effects are originating from coherent spin polarization exchange in a coupled spin system comprising the spin-polarized NV$^-$ center. Our results are of great practical importance allowing one to optimize the experimental conditions for probing LAC-derived lines in diamond crystals comprising NV$^-$ centers and for indirect detection and identification of other paramagnetic defect centers.