Probing stress and magnetism at high pressures with two-dimensional quantum sensors
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-09-01 |
| Journal | Nature Communications |
| Authors | G. He, Ruotian Gong, Zhipan Wang, Zhongyuan Liu, Jeonghoon Hong |
| Institutions | Washington University in St. Louis, Indiana University Bloomington |
| Citations | 6 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Probing Stress and Magnetism at High Pressures
Section titled âTechnical Documentation & Analysis: Probing Stress and Magnetism at High PressuresâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates a highly sensitive, integrated quantum sensing platform for extreme pressure environments, utilizing Boron-Vacancy (VB) centers in hexagonal Boron Nitride (hBN) directly within a Diamond Anvil Cell (DAC).
- Novel Sensor Integration: VB centers in a thin h$^{10}$B$^{15}$N flake (~100 nm) were transferred directly onto the diamond anvil culet, enabling nanoscale proximity sensing inside the high-pressure chamber.
- Enhanced Stress Sensitivity: The VB sensors exhibited a pressure susceptibility of (2$\pi$) x (43 $\pm$ 7) MHz/GPa, approximately three times stronger than conventional Nitrogen-Vacancy (NV) centers embedded in diamond anvils.
- Dual Sensing Capability: The platform simultaneously mapped local stress gradients (using NaCl medium) and imaged magnetic fields.
- Pressure-Induced Magnetism: The system successfully monitored a pressure-driven magnetic phase transition in the van der Waals ferromagnet Cr1+$\delta$Te2, observing a transition to a non-magnetic state around 0.5 GPa.
- Hardware Requirements: The experiment utilized Type IIa diamond anvils (400 ”m culet diameter) and custom-placed Platinum (Pt) wires (50 ”m width) for microwave delivery.
- Future Potential: This work paves the way for in situ characterization of pressure-induced phenomena, including superconductivity, novel magnetism, and mechanical deformation, requiring ultra-high-quality diamond substrates and integrated microwave structures.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Pressure Probed | 3.5 | GPa | VB ODMR contrast vanishes above this limit (using NaCl medium) |
| VB Pressure Susceptibility | (2$\pi$) x (43 $\pm$ 7) | MHz/GPa | Stress response, ~3x larger than NV centers in diamond |
| Zero-Field Splitting (Dgs) | (2$\pi$) x 3.48 | GHz | VB electronic spin triplet ground state (at 0 GPa) |
| Hyperfine Coupling Strength (Azz) | (2$\pi$) x 65.5 | MHz | At 0 GPa, attributed to 15N nuclei interaction |
| Magnetic Transition Pressure | ~0.5 | GPa | Ferromagnetic to non-magnetic transition in Cr1+$\delta$Te2 |
| External Magnetic Field (Bext) | 84 | G | Applied along the out-of-plane (z) axis |
| Diamond Anvil Culet Diameter | 400 | ”m | Used in the miniature Pasternak DAC |
| hBN Flake Thickness | ~100 | nm | Thin layer containing VB centers |
| Cr1+$\delta$Te2 Nanoflake Thickness | 50-100 | nm | Van der Waals magnet sample |
| Microwave Delivery Wire Width | 50 | ”m | Platinum (Pt) foil placed across the culet |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on precise material preparation and integration within a specialized high-pressure environment:
- DAC Preparation: A miniature Pasternak DAC was used with Type IIa diamond anvils (400 ”m culet). A stainless steel gasket was preindented and laser drilled (133 ”m diameter hole).
- Sensor Material Synthesis: Isotopically purified h$^{10}$B$^{15}$N crystals were grown via chemical vapor deposition (CVD) and subsequently irradiated with neutrons (1.4 x 1016 (1-h) neutrons per square centimeter) to create the VB spin defects.
- Heterostructure Assembly: The hBN flake (~100 nm) was transferred directly onto the diamond anvil culet. For magnetic studies, a Cr1+$\delta$Te2 nanoflake (50-100 nm) was stacked on top of the hBN layer.
- Microwave Integration: A 50 ”m wide Platinum (Pt) wire was placed across the heterostructure to deliver the coherent microwave field necessary for Optically Detected Magnetic Resonance (ODMR).
- Pressure Application and Calibration: Sodium Chloride (NaCl) was loaded as the quasi-hydrostatic pressure medium. Pressure was calibrated in situ using ruby R2 fluorescence shifts.
- Quantum Sensing: ODMR spectroscopy was performed at room temperature under an external magnetic field (Bext = 84 G) to measure the Zero-Field Splitting (ZFS) shift, which correlates directly to local stress and magnetic fields.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical need for ultra-high-quality diamond substrates and precision engineering for next-generation quantum sensing devices. 6CCVD is uniquely positioned to supply the foundational materials and customization services required to replicate and advance this work.
| Research Requirement | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| High-Quality Anvils | Optical Grade Single Crystal Diamond (SCD) | Provides the necessary mechanical strength, thermal conductivity, and optical transparency for Type IIa DAC anvils, ensuring reliable operation up to extreme pressures. |
| Ultra-Smooth Surfaces | Precision Polishing (Ra < 1 nm) | Guaranteed surface roughness (Ra < 1 nm for SCD) is crucial for stable transfer and integration of 2D materials (hBN, Cr1+$\delta$Te2$) and minimizing strain-induced noise in VB sensors. |
| Custom Dimensions | Custom Plate/Wafer Fabrication | We supply SCD and PCD plates in custom dimensions and thicknesses (SCD: 0.1 ”m - 500 ”m; PCD: up to 125 mm), allowing precise integration into specialized DAC systems (e.g., Pasternak cells requiring 400 ”m culets). |
| Microwave Delivery | Integrated Metalization Services | The experiment used a 50 ”m Pt wire. 6CCVD offers high-precision, internal metalization (Au, Pt, Pd, Ti, W, Cu) directly onto the diamond substrate. This enables the fabrication of integrated microwave structures (e.g., coplanar waveguides) for superior field homogeneity and coherence control, eliminating manual wire placement. |
| Hybrid Sensing Platforms | Boron-Doped Diamond (BDD) & NV Integration | For benchmarking or hybrid systems (as suggested in the Outlook), 6CCVD can supply SCD substrates with engineered NV centers or highly conductive Boron-Doped Diamond (BDD) for integrated electrical contacts. |
| Global Logistics | Global Shipping (DDU/DDP) | We ensure rapid, reliable global delivery of sensitive materials, supporting international research collaborations. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team provides expert consultation on material selection, defect engineering, and custom metalization layouts for similar high-pressure quantum sensing projects involving stress and magnetism. We assist researchers in optimizing diamond properties (purity, orientation, surface finish) to maximize sensor performance and stability in extreme environments.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Pressure serves as a fundamental tuning parameter capable of drastically modifying all properties of matter. The advent of diamond anvil cells (DACs) has enabled a compact and tabletop platform for generating extreme pressure conditions in laboratory settings. However, the limited spatial dimensions and ultrahigh pressures within these environments present significant challenges for conventional spectroscopy techniques. In this work, we integrate optical spin defects within a thin layer of two-dimensional (2D) materials directly into the high-pressure chamber, enabling an in situ quantum sensing platform for mapping local stress and magnetic environments up to 3.5 GPa. Compared to nitrogen-vacancy (NV) centers embedded in diamond anvils, our 2D sensors exhibit around three times stronger response to local stress and provide nanoscale proximity to the target sample in heterogeneous devices. We showcase the versatility of our approach by imaging both stress gradients within the high-pressure chamber and a pressure-driven magnetic phase transition in a room-temperature self-intercalated van der Waals ferromagnet, Cr<sub>1+ÎŽ</sub>Te<sub>2</sub>. Our work demonstrates an integrated quantum sensing device for high-pressure experiments, offering potential applications in probing pressure-induced phenomena such as superconductivity, magnetism, and mechanical deformation.