- 标题
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Scaling Phononic Quantum Networks of Solid-State Spins with Closed Mechanical Subsystems
摘要： Phononic quantum networks feature distinct advantages over photonic networks for on-chip quantum communications, providing a promising platform for developing quantum computers with robust solid-state spin qubits. Large mechanical networks including one-dimensional chains of trapped ions, however, have inherent and well-known scaling problems. In addition, chiral phononic processes, which are necessary for conventional phononic quantum networks, are difficult to implement in a solid-state system. To overcome these seemingly unsolvable obstacles, we have developed a new network architecture that breaks a large mechanical network into small and closed mechanical subsystems. This architecture is implemented in a diamond phononic nanostructure featuring alternating phononic crystal waveguides with specially designed band gaps. The implementation also includes nanomechanical resonators coupled to color centers through phonon-assisted transitions as well as quantum state transfer protocols that can be robust against the thermal environment.
关键词： quantum communications,diamond phononic nanostructure,Phononic quantum networks,quantum state transfer,solid-state spin qubits
更新于2025-09-10 09:29:36
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MORPHOLOGY OF DIAMOND SINGLE CRYSTALS GROWN IN THE Fe-Co-Mg-C SYSTEM
摘要： Diamond single crystals in a Fe-Co alloy with addition of 5 and 10 wt. % Mg by temperature gradient method were grown and their morphology was studied. For crystals obtained in the Fe-Co alloy with 5 wt. % Mg, the faces of octahedron, cube, rhomb-dodecahedron and tetragon-trioctahedron {311} were observed. When the magnesium content in the solvent-alloy increase up to 10 wt. % under the same growth conditions the tetragon-trioctahedron {311} faces on diamond crystals were absent. The topography of diamond crystals faces grown in different systems indicates that octahedron and cube are active growth forms with their growth pyramids, and rhomb-dodecahedron and tetragon-trioctahedron {311} are forms of passive growth.
关键词： A1.Crystal morphology,B1. Diamond,A2. Single crystal growth,A2. Growth from high temperature solutions
更新于2025-09-10 09:29:36
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Comparison of HPHT and LPHT annealing of Ib synthetic diamond
摘要： Defect transformations in type Ib synthetic diamond annealed at a temperature of 1870 °C under stabilizing pressure (HPHT annealing) and in hydrogen atmosphere at normal pressure (LPHT annealing) are compared. Spectroscopic data obtained on the samples before and after annealing prove that the processes of nitrogen aggregation and formation of nitrogen-nickel complexes are similar in both cases. Essential differences between HPHT and LPHT annealing are stronger graphitization at macroscopic imperfections and enhanced lattice distortions around point defects in the latter case. The lattice distortion around point defects is revealed as a considerable broadening of zero-phonon lines of "soft" (vacancy-related) optical centers. It was found that LPHT annealing may enhance overall intensity of luminescence of HPHT-grown synthetic diamonds.
关键词： nitrogen aggregation,graphitization,low pressure high temperature annealing,synthetic type Ib diamond,spectral broadening,high pressure high temperature annealing
更新于2025-09-10 09:29:36
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Single crystal diamond membranes and photonic resonators containing germanium vacancy color centers
摘要： Single crystal diamond membranes that host optically active emitters are highly attractive components for integrated quantum nanophotonics. In this work we demonstrate bottom-up synthesis of single crystal diamond membranes containing the germanium vacancy (GeV) color centers. We employ a lift-off technique to generate the membranes and perform chemical vapour deposition in a presence of a germanium source to realize the in-situ doping. Finally, we show that these membranes are suitable for engineering of photonic resonators such as microdisk cavities with quality factors of ~ 1500. The robust and scalable approach to engineer single crystal diamond membranes containing emerging color centers is a promising pathway for realization of diamond integrated quantum nanophotonic circuits on a chip.
关键词： germanium vacancy,Diamond,microring,nanophotonics,membranes,cavity
更新于2025-09-10 09:29:36
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Evidence for Primal sp <sup>2</sup> Defects at the Diamond Surface: Candidates for Electron Trapping and Noise Sources
摘要： Many advanced applications of diamond materials are now being limited by unknown surface defects, including in the fields of high power/frequency electronics and quantum computing and quantum sensing. Of acute interest to diamond researchers worldwide is the loss of quantum coherence in near-surface nitrogen-vacancy (NV) centers and the generation of associated magnetic noise at the diamond surface. Here for the first time is presented the observation of a family of primal diamond surface defects, which is suggested as the leading cause of band-bending and Fermi-pinning phenomena in diamond devices. A combination of density functional theory and synchrotron-based X-ray absorption spectroscopy is used to show that these defects introduce low-lying electronic trap states. The effect of these states is modeled on band-bending into the diamond bulk and it is shown that the properties of the important NV defect centers are affected by these defects. Due to the paramount importance of near-surface NV center properties in a growing number of fields, the density of these defects is further quantified at the surface of a variety of differently-treated device surfaces, consistent with best-practice processing techniques in the literature. The identification and characterization of these defects has wide-ranging implications for diamond devices across many fields.
关键词： surfaces,Fermi-level pinning,defects,diamond,NEXAFS
更新于2025-09-10 09:29:36
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Deterministic Arrays of Epitaxially Grown Diamond Nanopyramid <i>s</i> with Embedded Silicon-Vacancy Centers
摘要： The negatively charged silicon-vacancy center (SiV) in diamond is a potential high-quality source of single-indistinguishable photons for quantum information processing and quantum electrodynamics applications. However, when embedded in bulk diamond, this emitter suffers from both, relatively low extraction efficiency attributed to total internal reflection as well as nondeterministic location. On the other hand, its implementation in nanodiamonds is impeded by optical dephasing owing to their degraded surface quality. Here a robust and deterministic template-assisted bottom-up process for the creation of high-quality diamond nanopyramids incorporating SiVs is reported. This method employs a predefinition of high-precision nanopillars by e-beam lithography and dry etching, and subsequent epitaxial overgrowth during which Si atoms are introduced into diamond. The overgrown layer, including the nanopyramid arrays, is epitaxial as confirmed by comprehensive analyses. This diamond nanopyramid, hosting the SiVs, can pave the way toward efficient localized single-photon source arrays and potentially outshine nanodiamonds and nanosized structures prepared by a top-down method. The lateral confinement of the SiVs inside the deterministic nanosized pyramids enables their positioning at the center of cavities and optical structures for enhanced quantum efficiency and light–matter manipulation, and their employment as a system to explore collective coherent interactions between ensembles and confined light.
关键词： nanopyramids,field enhancement,spatial addressing,silicon-vacancy centers,diamond
更新于2025-09-10 09:29:36
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Magnetic Field Imaging of Superparamagnetic Particles Using High-Density, Perfectly Oriented NV Centers in Diamond CVD Film
摘要： The spatial and temporal resolutions of bio-imaging with magnetic nanoparticles (MNP) as a label and a diamond substrate as a magnetic field imager are investigated. To realize fast and accurate magnetic field imaging even for a substrate with unresolved hyperfine peaks, relative fluorescence is measured at four operation points corresponding to the steepest slopes of two dips in the ODMR spectrum. The (111) diamond substrate with a 3.5-μm thick chemical vapor deposition film with an NV density of 1.6 (cid:3) 1016 cm(cid:1)3 allows us to detect 1-μm MNPs scattered on its surface with an accumulated exposure time of 19 s under external DC magnetic field of 1.3 mT. Theoretical limit of temporal sensitivity is estimated to be more than four orders of magnitude smaller than measured. Although for measurement in culture medium, an objective lens with longer working distance is required and the condition will become somewhat worse, a spatiotemporal resolution of <1 s and <1 μm for the density and quality of the NV centers used in this study is expected if the already reported sensitivity enhancement technologies are further incorporated.
关键词： diamond,CVD,NV center,bio-imaging
更新于2025-09-10 09:29:36
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Increased nitrogen-vacancy centre creation yield in diamond through electron beam irradiation at high temperature
摘要： The nitrogen-vacancy (NV) centre is a fluorescent defect in diamond that is of critical importance for applications from ensemble sensing to biolabelling. Hence, understanding and optimising the creation of NV centres in diamond is vital for technological progress in these areas. We demonstrate that simultaneous electron irradiation and annealing of a high-pressure high-temperature diamond sample increases the NV centre creation efficiency from substitutional nitrogen defects by up to 117% with respect to a sample where the processes are carried out consecutively, but using the same process parameters. This increase in fluorescence is supported by visible and infrared absorption spectroscopy experiments. Our results pave the way for a more efficient creation of NV centres in diamond as well as higher overall NV densities in the future.
关键词： diamond,nitrogen-vacancy centre,high temperature,fluorescence,absorption spectroscopy,electron beam irradiation
更新于2025-09-10 09:29:36
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SOI wafer fabricated with a diamond BOX layer using surface activated bonding at room temperature
摘要： We propose a fabrication process for a silicon on insulator (SOI) wafer with a diamond buried oxide (BOX) layer by combining nanodiamond-seeding deposition and a surface-activated bonding technique for high-frequency and power device applications. The diamond layer was deposited on a base wafer by the spin-coating of nanodiamonds and microwave-plasma-enhanced chemical vapor deposition. The thermal conductivity of this deposited diamond layer was three times that of a conventional SiO2 layer. A silicon wafer was then bonded to the diamond layer at room temperature in ultrahigh vacuum without forming any voids. Additionally, this SOI wafer was used to fabricate devices at 1000 °C. Therefore, we believe that this SOI wafer with a diamond BOX layer and its fabrication process are important for the realization of self-heating devices such as next-generation high-frequency and power devices.
关键词： SOI wafer,surface-activated bonding,high-frequency devices,power devices,diamond BOX layer
更新于2025-09-10 09:29:36
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Growth of Structurally Perfect Diamond Single Crystals at High Pressures and Temperatures. Review
摘要： The investigations performed at high pressures and high temperatures (HTHP crystallization) have permitted clarifying the mechanism of phase transformations and carbon transport in solvent metals for diamond growth and elaborating methods for growing large-size structurally perfect diamond single crystals of types Ib, IIa, and IIb. The findings have provided the basis for the process of production of diamonds for applications in electronics, laser technology, precision machining operations, well drilling tools. The use of a large-volume six-punch high pressure apparatus makes it possible to grow diamond single crystals with a higher efficiency. It is estimated that this apparatus is capable of producing annually at least 1 mln carats of structurally perfect crystals of required types for various applications.
关键词： diamond single crystals,growth systems,temperature gradient method,high pressure apparatus
更新于2025-09-10 09:29:36