Sensing Individual Nuclear Spins with a Single Rare-Earth Electron Spin
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-04-29 |
| Journal | Physical Review Letters |
| Authors | Thomas Kornher, Da-Wu Xiao, Kangwei Xia, Fiammetta Sardi, Nan Zhao |
| Institutions | University of Stuttgart, Beijing Computational Science Research Center |
| Citations | 31 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Quantum Spin Sensing in Solid-State Hosts
Section titled āTechnical Documentation & Analysis: Quantum Spin Sensing in Solid-State HostsāThis document analyzes the research paper āSensing individual nuclear spins with a single rare-earth electron spinā and outlines how 6CCVDās advanced MPCVD diamond materials and fabrication services can accelerate and scale similar quantum technology research.
Executive Summary
Section titled āExecutive SummaryāThis research successfully demonstrates coherent control and nuclear spin sensing using a single rare-earth ion (CeĀ³āŗ) in a Yttrium Orthosilicate (YSO) host crystal, providing critical insights for solid-state quantum memory development.
- Core Achievement: Coherent manipulation of an individual CeĀ³āŗ electron spin, achieving a coherence time (Tā) of 124 Āµs at cryogenic temperatures (T ā 8K).
- Quantum Sensing: Successful detection and isolation of proximal 29Si nuclear spins using dynamic decoupling (CPMG) sequences, validating coupled nuclear spins as quantum memory resources.
- Methodology: Utilized Optically Detected Magnetic Resonance (ODMR) and Hahn echo sequences under a 970 Gauss magnetic field, combined with Solid Immersion Lenses (SILs) for enhanced optical resolution.
- Material Relevance: The study confirms the viability of hybrid quantum systems (electron spin coupled to long-lived nuclear spins) for quantum error correction schemes.
- 6CCVD Value Proposition: While YSO was the host, 6CCVD specializes in Single Crystal Diamond (SCD), the superior, scalable platform for hosting quantum defects (NV, SiV) that offer similar or better performance, often at higher temperatures.
- Scalability: 6CCVD provides the high-purity SCD substrates and custom fabrication necessary to transition these complex sensing techniques into scalable, integrated diamond quantum devices.
Technical Specifications
Section titled āTechnical SpecificationsāThe following hard data points were extracted from the experimental results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Electron Spin Coherence Time (Tā) | 124 Ā± 5 | Āµs | Hahn echo measurement of CeĀ³āŗ in YSO. |
| Electron Spin Relaxation Time (Tā) | 610 / 280 | Āµs | Measured at T = 7.8K / 8.5K, respectively. |
| Inhomogeneous Broadening (Tā*) | 310 | ns | Ramsey measurement of CeĀ³āŗ. |
| Magnetic Field (B) | 970 | Gauss | Applied parallel to the optical beam (b-axis of YSO). |
| Magnetic Resonance Frequency (MW) | 1930.5 | MHz | Used for ODMR measurements (gce ā 1.4). |
| Rabi Frequency | 5.6 | MHz | Coherent spin manipulation; decay time 2 Āµs. |
| Host Material Purity (CeĀ³āŗ) | 0.3 | ppb | Estimated residual density in ultra-pure YSO crystal. |
| Optical Excitation Wavelength | 355 | nm | Picosecond pulsed laser for 4f ā 5d excitation. |
| Zero-Phonon Line (ZPL) | 371 | nm | Characteristic CeĀ³āŗ fluorescence at cryogenic T. |
| Proximal 29Si Distance | < 6 | Ć | Distance required for detectable hyperfine coupling. |
| Nuclear Spin Coherence (Estimated) | ~10 | ms | Estimated Tā for 29Si nuclear spin in YSO. |
Key Methodologies
Section titled āKey MethodologiesāThe experiment relied on precise material preparation, cryogenic operation, and advanced microwave/optical control sequences:
- Sample Preparation & Optics: Ultra-pure YSO crystal (0.01% CeĀ³āŗ doped) was used. Solid Immersion Lenses (SILs) were fabricated on the surface using Focused Ion Beam (FIB) milling to improve collection efficiency and spatial resolution.
- Cryogenic Operation: Experiments were conducted in a cold-finger cryostat at temperatures ranging from T ā 8K down to 3.8K, with the sample mounted on a permanent magnet providing the 970 Gauss B-field.
- Spin Initialization: A picosecond pulsed 355 nm laser was used for off-resonant excitation. Optical polarization was achieved by selectively driving a spin-flip transition, pumping the electron spin into an optically ādarkā state.
- Spin Control & Readout: Microwave (MW) radiation (1930.5 MHz) was delivered via proximal copper wires for coherent spin manipulation (Rabi oscillations) and Optically Detected Magnetic Resonance (ODMR).
- Coherence Measurement: Free Induction Decay (FID) quantified inhomogeneous broadening (Tā*). Hahn spin echo sequences were used to measure the long coherence time (Tā = 124 Āµs) and reveal periodic revivals related to the 89Y spin bath.
- Nuclear Spin Decoupling: Carr-Purcell-Meiboom-Gill (CPMG-N) dynamic decoupling sequences were applied to isolate the CeĀ³āŗ electron spin from the noisy nuclear bath, enabling the detection of nearby individual 29Si nuclear spins.
6CCVD Solutions & Capabilities
Section titled ā6CCVD Solutions & CapabilitiesāThis research validates the critical role of solid-state hosts in developing hybrid quantum registers. While YSO was used, MPCVD diamond is the industry-leading platform for scalable quantum sensing and memory due to its superior thermal, mechanical, and quantum properties (e.g., stable NV and SiV centers).
6CCVD is uniquely positioned to supply the materials and processing required to replicate and advance this research using diamond.
Applicable Materials for Quantum Sensing
Section titled āApplicable Materials for Quantum Sensingā| Research Requirement | 6CCVD Material Recommendation | Technical Advantage |
|---|---|---|
| Ultra-Pure Host Material (Minimizing background spin noise) | Electronic Grade Single Crystal Diamond (SCD) | Extremely low intrinsic nitrogen concentration (P1 centers), minimizing decoherence from background spins, crucial for achieving long Tā. |
| High-Density Spin Bath Control (Coupling to 29Si/89Y) | Isotopically Purified SCD (e.g., < 0.1% 13C) | Provides a quiet nuclear spin environment, allowing researchers to precisely control and couple to engineered defects (like SiV or NV) or implanted nuclear spins (like 29Si). |
| Conductive Electrodes/Doping (For potential BDD-based devices) | Boron-Doped Diamond (BDD) | Available in custom thicknesses (0.1 Āµm to 500 Āµm) for creating conductive layers or specialized defect creation/charge state control. |
Customization Potential for Device Integration
Section titled āCustomization Potential for Device IntegrationāThe paper highlights the necessity of integrating optical structures (SILs) and MW components (copper wires) directly onto the host material. 6CCVD offers comprehensive in-house fabrication services to meet these demands:
- Custom Dimensions & Thickness: We supply SCD plates/wafers in custom dimensions, with thicknesses ranging from 0.1 Āµm up to 500 Āµm, suitable for integration into complex cryogenic setups.
- Precision Polishing: Our SCD materials are polished to an industry-leading surface roughness of Ra < 1 nm, which is essential for minimizing optical scattering losses and maximizing the efficiency of integrated optical structures like SILs.
- Advanced Metalization: We offer internal metalization capabilities, including the deposition of Ti, Pt, Au, Pd, W, and Cu. This is critical for fabricating the high-frequency MW transmission lines and electrodes required for ODMR and dynamic decoupling sequences (CPMG).
- Precision Processing: We provide custom laser cutting and etching services for creating specific geometries, alignment features, and integration points necessary for mounting and wire bonding in cryostats.
Engineering Support
Section titled āEngineering Supportā6CCVDās in-house team of PhD material scientists and engineers specializes in the growth and characterization of MPCVD diamond for quantum applications. We offer consultation on:
- Material Selection: Assisting researchers in selecting the optimal diamond grade (SCD purity, isotopic composition) for replicating or extending this Quantum Memory/Spin Sensing research using NV or SiV centers.
- Defect Engineering: Guidance on post-growth processing (e.g., implantation, annealing) to achieve the desired density and location of quantum defects.
- Device Integration: Technical support for optimizing surface preparation and metalization schemes for high-performance MW and optical coupling.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Rare-earth related electron spins in crystalline hosts are unique material systems, as they can potentially provide a direct interface between telecom band photons and long-lived spin quantum bits. Specifically, their optically accessible electron spins in solids interacting with nuclear spins in their environment are valuable quantum memory resources. Detection of nearby individual nuclear spins, so far exclusively shown for few dilute nuclear spin bath host systems such as the nitrogen-vacancy center in diamond or the silicon vacancy in silicon carbide, remained an open challenge for rare earths in their host materials, which typically exhibit dense nuclear spin baths. Here, we present the electron spin spectroscopy of single Ce^{3+} ions in a yttrium orthosilicate host, featuring a coherence time of T_{2}=124 Ī¼s. This coherent interaction time is sufficiently long to isolate proximal ^{89}Y nuclear spins from the nuclear spin bath of ^{89}Y. Furthermore, it allows for the detection of a single nearby ^{29}Si nuclear spin, native to the host material with ā¼5% abundance. This study opens the door to quantum memory applications in rare-earth ion related systems based on coupled environmental nuclear spins, potentially useful for quantum error correction schemes.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal SourceāReferences
Section titled āReferencesā- 2015 - Engineering the Atom-Photon Interaction