Photoluminescence at the ground-state level anticrossing of the nitrogen-vacancy center in diamond - A comprehensive study
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-01-20 |
| Journal | Physical review. B./Physical review. B |
| Authors | Viktor IvĂĄdy, Huijie Zheng, Arne Wickenbrock, Lykourgos Bougas, Georgios Chatzidrosos |
| Institutions | GSI Helmholtz Centre for Heavy Ion Research, Linköping University |
| Citations | 32 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research provides a comprehensive joint experimental and theoretical analysis of the photoluminescence (PL) signatures of Nitrogen-Vacancy (NV) centers in diamond at the Ground State Level Anti-Crossing (GSLAC) region (Bz â 102.4 mT). This work is critical for advancing microwave-free quantum sensing and spectroscopy applications.
- Unique Defect Signatures: The study successfully identifies and characterizes unique PL signatures arising from interactions with external fields, 13C nuclear spins, P1 centers, and other NV centers, enabling precise identification of dominant environmental couplings in diamond samples.
- Microwave-Free Sensing Advancement: The detailed analysis of parasitic interactions (e.g., transverse fields, strain) provides necessary information to avoid misinterpretation of PL signals, crucial for developing high-sensitivity, microwave-free magnetometry and spectroscopy.
- 15NV Center Utility: It is demonstrated that the less abundant 15NV center can be utilized for GSLAC applications, offering comparable or superior performance, potentially leading to better resolution and lower sensitivity to external perturbations due to its simpler energy level structure.
- Enhanced DNP Mechanism: A novel Dynamic Nuclear Polarization (DNP) pathway is revealed: the NV center directly polarizes nuclear spins coupled to P1 centers through an effective giant nuclear g-factor, opening new directions for DNP without relying on nuclear spin diffusion.
- Defect Concentration Tool: The GSLAC PL signal linewidth (FWHM) is shown to depend linearly on the concentration of paramagnetic point defects (P1 centers), establishing a novel, optical method for measuring defect concentration in the vicinity of NV centers (slope â 20 ”T/ppm).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| GSLAC Longitudinal Magnetic Field (Bz) | ±102.4 | mT | Magnetic field required for the ground state level anticrossing. |
| 14NV Zero-Field Splitting (D) | 2868.91 | MHz | Intrinsic electronic spin splitting of the NV center. |
| 14N Nuclear Quadrupole Splitting (Q) | -5.01 | MHz | Intrinsic nuclear quadrupole interaction parameter. |
| 14NV Transverse Field FWHM Slope (Theoretical) | 3.36 | mTmT-1 | Linewidth broadening gradient due to transverse magnetic field. |
| 14NV Transverse Field FWHM Slope (Experimental) | 2.3 ± 0.1 | mTmT-1 | Measured linewidth broadening gradient (Sample IS, 12C depleted). |
| P1 Concentration FWHM Slope (Theoretical) | â 20 | ”T/ppm | Gradient used to measure spin defect concentration via PL linewidth. |
| Optical Pumping Dwell Time (Simulation) | 3 | ”s | Coherent time evolution duration in DNP simulations. |
| 13C Abundance (Natural) | 1.07 | % | Used in W4 and F11 samples. |
| P1 Concentration Range (Samples Studied) | 1 to 200 | ppm | Range of P1 defect concentrations investigated experimentally. |
| ODMR Contrast (C) | 0.3 | - | Experimentally attainable value used in PL intensity approximation. |
Key Methodologies
Section titled âKey Methodologiesâ- Theoretical Modeling (Extended Lindblad Formalism): Employed to simulate spin-relaxation of the central NV center surrounded by a bath of environmental spins (13C, P1, other NV centers).
- Density Matrix Propagation: Used for modeling the effects of external fields on a single NV center, propagating the density matrix over a finite time interval (0.1 ms) according to the master equation.
- DNP Simulation Cycle: Simulated optical excitation cycles consisting of two steps: 1) coherent ground state time evolution (dwell time tGS = 3 ”s), and 2) spin-selective optical excited state process modeled by a projection operator.
- Cluster Approximation: The many-spin system was divided into clusters. A second-order cluster approximation (N=2) was used for the 13C spin bath to include 13C-13C coupling, while a first-order approximation was used for electron spin defects (P1, NV) due to their shorter coherence times.
- Hyperfine Coupling Determination: Hyperfine coupling tensors between the central NV center and nuclear spins were calculated using first principles Density Functional Theory (DFT).
- Experimental PL Measurement Setup: Photoluminescence measurements were conducted using a custom-built electromagnet capable of providing magnetic fields up to 110 mT, coupled with a computer-controlled 3-D translation and rotation stage for precise alignment.
- Ensemble Averaging: Ensemble averaged PL spectra were obtained by simulating 100 random spin defect configurations to represent a realistic spin bath concentration.
Commercial Applications
Section titled âCommercial Applicationsâ- Microwave-Free Quantum Sensing: Utilizing the GSLAC PL signal for high-sensitivity magnetometry and electric field sensing in environments where high-power microwave driving is undesirable (e.g., biological systems, medical diagnostics).
- Hyperpolarized MRI/NMR Agents: Leveraging the demonstrated efficient DNP mechanisms (both 13C and P1-coupled nuclear spins) to create hyperpolarized diamond samples, which can transfer spin polarization to adjacent nuclear spins for improved Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) methods.
- Diamond Material Quality Control: Using the measured linear dependence of the PL linewidth on P1 concentration (â 20 ”T/ppm) as a rapid, non-destructive optical tool to measure and map spin defect concentration in synthesized diamond substrates.
- Solid-State Quantum Computing: Exploiting the coupling of mutually aligned NV centers at the GSLAC for potential microwave-free quantum gate operations, particularly utilizing the 15NV center due to its better controllability (larger hyperfine splitting, fewer crossing states).
- Spectroscopy of Environmental Couplings: Applying the unique PL signatures to precisely characterize local strain, electric fields, and defect environments in diamond, essential for optimizing NV center performance in quantum devices.
View Original Abstract
The nitrogen-vacancy center (NV center) in diamond at magnetic fields\ncorresponding to the ground state level anticrossing (GSLAC) region gives rise\nto rich photoluminescence (PL) signals due to the vanishing energy gap between\nthe electron spin states, which enables to have an effect on the NV centerâs\nluminescence for a broad variety of environmental couplings. In this article we\nreport on the GSLAC photoluminescence signature of NV ensembles in different\nspin environments at various external fields. We investigate the effects of\ntransverse electric and magnetic fields, P1 centers, NV centers, and the\n$^{13}$C nuclear spins, each of which gives rise to a unique PL signature at\nthe GSLAC. The comprehensive analysis of the couplings and related optical\nsignal at the GSLAC provides a solid ground for advancing various\nmicrowave-free applications at the GSLAC, including but not limited to\nmagnetometry, spectroscopy, dynamic nuclear polarization (DNP), and nuclear\nmagnetic resonance (NMR) detection. We demonstrate that not only the most\nabundant $^{14}$NV center but the $^{15}$NV can also be utilized in such\napplications and that nuclear spins coupled to P1 centers can be polarized\ndirectly by the NV center at the GSLAC, through a giant effective nuclear\n$g$-factor arising from the NV center-P1 center-nuclear spin coupling. We\nreport on new alternative for measuring defect concentration in the vicinity of\nNV centers and on the optical signatures of interacting, mutually aligned NV\ncenters.\n