Hyperfine Interactions in the NV-13C Quantum Registers in Diamond Grown from the Azaadamantane Seed

At a Glance

Metadata	Details
Publication Date	2021-05-14
Journal	Nanomaterials
Authors	А. П. Низовцев, Aliaksandr Pushkarchuk, S. Ya. Kilin, Nikolai I. Kargin, А. С. Гусев
Institutions	National Research Nuclear University MEPhI, Center for Integrated Quantum Science and Technology
Citations	7
Analysis	Full AI Review Included

Technical Documentation & Analysis: Deterministic NV-¹³C Quantum Registers via Seeded Diamond Growth

Reference Paper: Nizovtsev et al. (2021). Hyperfine Interactions in the NV-¹³C Quantum Registers in Diamond Grown from the Azaadamantane Seed. Nanomaterials, 11(5), 1303.

Executive Summary

This research validates a critical bottom-up approach for creating deterministic quantum registers (NV-¹³C spin systems) in diamond, moving beyond probabilistic implantation methods.

Core Achievement: Prediction of unique hyperfine interaction (hfi) characteristics for NV centers coupled to ¹³C nuclear spins derived from isotopically substituted azaadamantane seeds.
Deterministic Fabrication: The methodology uses chemically synthesized organic molecules (azaadamantane, C₉H₁₅N) containing ¹³C in defined positions as seeds for diamond growth.
Quantum Fingerprint: Density Functional Theory (DFT) simulations provide precise values for the hfi-induced splitting ($\Delta_0$) of the NV center’s $m_s = \pm 1$ sublevels (ranging from 178 kHz to 134 MHz).
Validation Tool: These predicted $\Delta_0$ values serve as an essential “fingerprint” for researchers to identify the specific NV-¹³C configuration via high-resolution Optically Detected Magnetic Resonance (ODMR) spectroscopy.
Material Requirement: Success hinges on using high-purity, low-strain diamond material to achieve the necessary narrow ODMR linewidths (< 0.1 MHz) required to resolve the hyperfine structure.
Application: This work is foundational for developing scalable quantum memory, quantum sensing, and metrology devices utilizing coupled electron (NV) and nuclear (¹³C) spins.

Technical Specifications

The following hard data points were extracted from the DFT simulations and experimental context described in the paper.

Parameter	Value	Unit	Context
Maximum Hfi Splitting ($\Delta_0$)	134,100	kHz	Nearest neighbor ¹³C (NV3/4-C(4/5/6) systems)
Minimum Hfi Splitting ($\Delta_0$)	178	kHz	NV1-C(414) system
Maximum Axial Hfi ($A_{zz}$)	136,870	kHz	Component along the NV symmetry axis
Maximum Transverse Hfi ($A_{nd}$)	19,964	kHz	Component perpendicular to the NV axis
ODMR Linewidth (High-Res $\Gamma$)	0.1	MHz	Required resolution for resolving hyperfine structure
ODMR Linewidth (Low-Res $\Gamma$)	3	MHz	Linewidth observed in current nanodiamond experiments
External Magnetic Field (B)	4.7 to 13	G	Field used for ODMR simulation
HPHT Synthesis Temperature (T)	4000	K	Low-temperature synthesis condition (Ref [31])
HPHT Synthesis Pressure (P)	10	GPa	Low-temperature synthesis condition (Ref [31])

Key Methodologies

The research relies on a multi-step process combining advanced chemical synthesis, high-pressure growth, and quantum chemical simulation.

Isotopic Seed Preparation: Synthesis of 1- or 2-azaadamantane molecules (C₉H₁₅N) where specific ¹²C atoms are replaced by isotopic ¹³C atoms, ensuring deterministic placement of the nuclear spin.
Diamond Growth: High-Pressure, High-Temperature (HPHT) synthesis (T=4000 K, P=10 GPa) is used to grow nanodiamonds using the substituted azaadamantane molecules as seeds.
NV Center Formation: The grown nanocrystals undergo electron irradiation followed by annealing. This process causes vacancies (V) to migrate and bond with the nitrogen (N) atom from the seed, forming the NV center.
Quantum Chemical Simulation (DFT): Density Functional Theory (DFT) is applied to the H-terminated C₅₁₀[NV]-H₂₅₂ cluster model to calculate the full hyperfine interaction (hfi) matrices ($A_{KL}$) for all possible NV center orientations (V1-V8) relative to the ¹³C positions in the seed.
ODMR Prediction: The calculated hfi matrices are used to predict the hfi-induced splitting ($\Delta_0$) of the NV center’s $m_s = \pm 1$ sublevels, providing a unique spectral signature for each specific NV-¹³C configuration.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the high-quality, low-strain MPCVD diamond required to replicate and scale this deterministic quantum register research into macroscopic devices.

Applicable Materials

The successful resolution of the hyperfine structure requires extremely low background noise and minimal strain broadening.

Material Requirement	6CCVD Solution	Technical Rationale
Low Background ¹³C	High-Purity SCD (Optical Grade)	We offer SCD with controlled isotopic purity (< 0.1% ¹³C) to ensure that the hfi signal is dominated solely by the deterministically placed ¹³C atoms from the seed, minimizing spectral clutter.
Low Strain / High Coherence	Optical Grade SCD Wafers	Our SCD material is grown via MPCVD, resulting in superior crystalline quality (Ra < 1nm polishing) and low internal strain, which is critical for achieving the required narrow ODMR linewidths (< 0.1 MHz) necessary to resolve the predicted hyperfine splittings.
Scaling to Devices	PCD Substrates (up to 125mm)	For transitioning from nanodiamonds to integrated quantum devices, 6CCVD provides large-area Polycrystalline Diamond (PCD) wafers up to 125mm in diameter, offering a robust platform for scalable fabrication.

Customization Potential

To move this research from simulation to integrated quantum devices, precise material engineering is essential. 6CCVD offers full customization capabilities:

Custom Dimensions: We provide SCD plates and PCD wafers up to 125mm, allowing researchers to scale their seeded growth experiments from nanocrystals to macroscopic substrates.
Thickness Control: Precise control over the active layer thickness is available, ranging from 0.1µm to 500µm for both SCD and PCD, and substrates up to 10mm thick.
Metalization Services: For integrating diamond into ODMR/ESR setups, 6CCVD offers in-house custom metalization (e.g., Ti/Pt/Au, W, Cu) for creating microwave waveguides, electrodes, or contact pads directly on the diamond surface.
Precision Fabrication: We provide advanced laser cutting and shaping services to produce custom geometries required for specific quantum device architectures.

Engineering Support

The complexity of controlling NV orientation and minimizing strain in seeded growth requires specialized expertise.

6CCVD’s in-house PhD team specializes in material selection and optimization for solid-state quantum applications. We offer consultation on:

Strain Engineering: Assisting researchers in selecting the optimal diamond growth parameters to minimize strain, which is crucial for achieving the high spectral resolution needed to measure the predicted $\Delta_0$ values accurately.
Isotopic Control: Guidance on utilizing isotopically purified diamond substrates to maximize the signal-to-noise ratio of the deterministically placed ¹³C quantum memory.
NV Center Optimization: Support for post-growth processing (irradiation and annealing recipes) to maximize the yield and control the orientation of NV centers relative to the seed.

Call to Action: For custom specifications or material consultation regarding deterministic NV-¹³C quantum register projects, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Nanostructured diamonds hosting optically active paramagnetic color centers (NV, SiV, GeV, etc.) and hyperfine-coupled with them quantum memory 13C nuclear spins situated in diamond lattice are currently of great interest to implement emerging quantum technologies (quantum information processing, quantum sensing and metrology). Current methods of creation such as electronic-nuclear spin systems are inherently probabilistic with respect to mutual location of color center electronic spin and 13C nuclear spins. A new bottom-up approach to fabricate such systems is to synthesize first chemically appropriate diamond-like organic molecules containing desired isotopic constituents in definite positions and then use them as a seed for diamond growth to produce macroscopic diamonds, subsequently creating vacancy-related color centers in them. In particular, diamonds incorporating coupled NV-13C spin systems (quantum registers) with specific mutual arrangements of NV and 13C can be obtained from anisotopic azaadamantane molecule. Here we predict the characteristics of hyperfine interactions (hfi) for the NV-13C systems in diamonds grown from various isotopically substituted azaadamantane molecules differing in 13C position in the seed, as well as the orientation of the NV center in the post-obtained diamond. We used the spatial and hfi data simulated earlier for the H-terminated cluster C510[NV]-H252. The data obtained can be used to identify (and correlate with the seed used) the specific NV-13C spin system by measuring, e.g., the hfi-induced splitting of the mS = ±1 sublevels of the NV center in optically detected magnetic resonance (ODMR) spectra being characteristic for various NV-13C systems.

Tech Support

Original Source

DOI: https://doi.org/10.3390/nano11051303

References

2013 - The nitrogen-vacancy color centre in diamond [Crossref]
2013 - Quantum control over Single Spins in Diamond [Crossref]
2014 - Magnetometry with nitrogen-vacancy defects in diamond [Crossref]
2014 - Nitrogen-Vacancy Centers in Diamond: Nanoscale Sensors for Physics and Biology [Crossref]
2017 - Vacancy-impurity centers in diamond: Prospects for synthesis and applications [Crossref]
2017 - Coherence Properties and Quantum Control of Silicon Vacancy Color Centers in Diamond [Crossref]
2018 - Quantum technologies with optically interfaced solid-state spins [Crossref]
2012 - Robust dynamical decoupling [Crossref]
2012 - High-resolution spectroscopy of single NV defects coupled with nearby 13C nuclear spins in diamond [Crossref]