Cross-relaxation studies with optically detected magnetic resonances in nitrogen-vacancy centers in diamond in external magnetic field
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-04-09 |
| Journal | Physical review. B./Physical review. B |
| Authors | Reinis Lazda, Laima Busaite, Andris BÄrziĆĆĄ, JÄnis Ć mits, F. Gahbauer |
| Institutions | University of Latvia, GSI Helmholtz Centre for Heavy Ion Research |
| Citations | 13 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Cross-Relaxation in NV-Diamond
Section titled âTechnical Documentation & Analysis: Cross-Relaxation in NV-DiamondâExecutive Summary
Section titled âExecutive SummaryâThis research successfully utilized continuous-wave Optically Detected Magnetic Resonance (CW ODMR) to analyze cross-relaxation (CR) dynamics between Nitrogen-Vacancy (NV) centers and Substitutional Nitrogen (P1 centers) in diamond. This work is foundational for advanced quantum sensing and computing applications.
- Core Achievement: Demonstrated that CW ODMR is a viable method for studying complex spin dynamics, specifically the CR process between NV (S=1) and P1 (S=1/2) centers.
- Material Requirement: The study required a diamond crystal with a relatively high concentration of substitutional nitrogen (approx. 200 ppm 14N) to maximize CR signal contrast.
- Key Observation Points: CR phenomena were observed at axial magnetic fields near 51.2 mT (NV-P1) and 59.0 mT (NVon-NVoff).
- Methodology: MW fields (1.3-1.6 GHz and 4.1-4.6 GHz) were applied to drive ms = 0 â ms = ±1 transitions, leading to increased effective relaxation rates and subsequent changes in ODMR signal contrast and width.
- Quantum Relevance: The improved understanding of NV-P1 interactions and hyperfine mixing is critical for designing robust NV-diamond devices for quantum memory, q-bits, and hyperpolarization of large molecules.
- 6CCVD Value Proposition: 6CCVD specializes in MPCVD diamond, offering superior control over nitrogen concentration and crystal purity, enabling researchers to precisely tune the material properties required to replicate or extend these CR studies.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental setup and results described in the paper:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Nitrogen Concentration (Initial) | 200 | ppm | 14N in HPHT diamond crystal |
| Crystal Orientation | (100) | Surface Cut | Used for experimental setup |
| Electron Irradiation Dose | 1018 | e (cm-2) | NV center creation |
| Annealing Temperature | 750 | °C | Post-irradiation processing (3 hours) |
| NV-P1 Cross-Relaxation Field | 51.2 | mT | Axial magnetic field value (Central Peak E) |
| NVon-NVoff Cross-Relaxation Field | 59.0 | mT | Axial magnetic field value |
| Ground-State Level Anti-Crossing (GSLAC) | 102.4 | mT | Used for crystal alignment |
| Low-Frequency MW Range | 1.3 to 1.6 | GHz | ms = 0 â ms = -1 NV transitions |
| High-Frequency MW Range | 4.1 to 4.6 | GHz | ms = 0 â ms = +1 NV transitions |
| NV Ground-State Zero-Field Splitting (Dg) | 2870 | MHz | Approximately 2.87 GHz |
| Sensing Volume Dimensions | 0.4 x 0.4 x 0.35 | mm3 | Determined by optical fiber and diamond |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on specific material preparation and continuous-wave measurement techniques to observe the cross-relaxation phenomena:
- Substrate Selection: A high-pressure, high-temperature (HPHT) diamond crystal with a (100) surface cut and a high initial concentration of 14N (around 200 ppm) was chosen.
- NV Center Generation: The crystal was irradiated with a high dose of electrons (1018 e (cm-2) at 10 MeV) to generate vacancies.
- Thermal Processing: Post-irradiation annealing was performed for 3 hours at 750 °C to mobilize vacancies and facilitate the formation of negatively charged NV centers (NV-).
- Crystal Alignment: The diamond was precisely aligned in the external magnetic field by monitoring laser-induced fluorescence, targeting the known GSLAC feature near 102.4 mT.
- CW ODMR Measurement: Continuous-wave Optically Detected Magnetic Resonance was performed using a 532 nm green laser for optical initialization and excitation. Red fluorescence was collected and separated using a dichroic mirror and long-pass filter.
- Microwave (MW) Delivery: MW radiation, generated by function generators and power amplifiers, was delivered via a copper wire placed in close proximity (< 1 mm) to the diamond sample.
- Data Analysis: ODMR signal contrast (1 - Fmin / Fmax) and width were analyzed across varying magnetic fields to identify and characterize the positions and amplitudes of the cross-relaxation resonance peaks.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD provides the high-quality, customizable MPCVD diamond materials necessary to replicate, control, and advance the quantum research presented in this paper. Our capabilities ensure precise material engineering for optimal NV center performance.
Applicable Materials
Section titled âApplicable MaterialsâThe study used HPHT diamond with high nitrogen content (200 ppm). 6CCVD offers superior alternatives via MPCVD:
- Nitrogen-Doped Single Crystal Diamond (SCD): To replicate the high P1 center concentration (200 ppm 14N) required for strong NV-P1 cross-relaxation studies, 6CCVD can precisely control nitrogen doping during MPCVD growth, ensuring uniform P1 distribution across large wafers.
- Ultra-High Purity SCD (N < 1 ppb): For extending this research into high-coherence quantum applications (q-bits, quantum memory), researchers require minimal background P1 noise. 6CCVD provides ultra-low nitrogen SCD substrates, which can then be selectively implanted and annealed to create isolated, high-coherence NV centers.
- Custom Substrates: We offer SCD substrates up to 500 ”m thick and large PCD wafers up to 125 mm in diameter, enabling both fundamental research and eventual device scale-up.
Customization Potential
Section titled âCustomization Potentialâ6CCVDâs in-house engineering capabilities directly address the needs of advanced quantum experiments:
| Requirement from Paper/Application | 6CCVD Custom Solution | Benefit to Researcher |
|---|---|---|
| Substrate Size/Shape | Custom Plates/Wafers up to 125 mm (PCD) or large SCD plates. | Enables integration into complex setups and future device scaling. |
| Surface Quality | Precision Polishing (SCD: Ra < 1 nm; PCD: Ra < 5 nm). | Essential for surface-based sensing and minimizing optical scattering losses. |
| MW Delivery | Custom Metalization (Au, Pt, Ti, Cu, Pd, W). | Allows for integrated on-chip microwave antennas, replacing external copper wires and improving MW field homogeneity and Rabi frequency control. |
| Defect Engineering | Controlled Doping (N, B) and Post-Processing Support. | Provides substrates optimized for specific NV/P1 concentrations, crucial for tuning CR rates and coherence times (T2). |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and engineers provides authoritative support for complex quantum projects. We assist researchers in selecting the optimal diamond material (SCD or PCD) and processing parameters (doping, orientation, thickness) required for NV-P1 Cross-Relaxation and Quantum Sensing projects. We ensure the material specifications meet the stringent requirements for high-fidelity ODMR and spin manipulation.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. Global shipping (DDU default, DDP available) is provided for all orders.
View Original Abstract
In this paper cross-relaxation between nitrogen-vacancy (NV) centers and substitutional nitrogen in a diamond crystal was studied. It was demonstrated that optically detected magnetic resonance signals (ODMR) can be used to measure these signals successfully. The ODMR were detected at axial magnetic field values around 51.2mT in a diamond sample with a relatively high (200ppm) nitrogen concentration. We observed transitions that involve magnetic sublevels that are split by the hyperfine interaction. Microwaves in the frequency ranges from 1.3 GHz to 1.6 GHz ($m_S=0\longrightarrow m_S=-1$ NV transitions) and from 4.1 to 4.6 GHz ($m_S=0\longrightarrow m_S=+1$ NV transitions) were used. To understand the cross-relaxation process in more detail and, as a result, reproduce measured signals more accurately, a model was developed that describes the microwave-initiated transitions between hyperfine levels of the NV center that are undergoing anti-crossing and are strongly mixed in the applied magnetic field. Additionally, we simulated the extent to which the microwave radiation used to induce ODMR in the NV center also induced transitions in the substitutional nitrogen via cross-relaxation. The improved understanding of the NV processes in the presence of a magnetic field will be useful for designing NV-diamond-based devices for a wide range of applications from implementation of q-bits to hyperpolarization of large molecules to various quantum technological applications such as field sensors.