A5029842480- Diamond and Carbon-based Materials Research
- High-pressure geophysics and materials
- Force Microscopy Techniques and Applications
- Semiconductor materials and devices
- Atomic and Subatomic Physics Research
- Electronic and Structural Properties of Oxides
- Advanced Fiber Laser Technologies
- Magnetic properties of thin films
- Mechanical and Optical Resonators
- Ion-surface interactions and analysis
- Quantum optics and atomic interactions
- Metal and Thin Film Mechanics
- Quantum and electron transport phenomena
- Quantum Information and Cryptography
- Physics of Superconductivity and Magnetism
- Silicon Carbide Semiconductor Technologies
- Laser Material Processing Techniques
- Magneto-Optical Properties and Applications
- Magnetic Field Sensors Techniques
- Advanced Materials Characterization Techniques
- Advanced Surface Polishing Techniques
- Silicon and Solar Cell Technologies
- Advanced NMR Techniques and Applications
- Fullerene Chemistry and Applications
- Magnetic Properties and Applications
Kyoto University
2016-2025
Kyoto University Institute for Chemical Research
2016-2025
Spintronics Research Network of Japan
2017-2025
High Energy Accelerator Research Organization
2023-2025
International Center for Quantum-field Measurement Systems for Studies of the Universe and Particles
2023-2025
Instituto de Investigaciones Químicas
2023-2025
Kyoto Bunkyo University
2017-2023
National Institute of Advanced Industrial Science and Technology
2004-2022
Kanazawa University
2022
Japan Advanced Institute of Science and Technology
2021
Robust entanglement at room temperature is a necessary requirement for practical applications in quantum technology. We demonstrate the creation of bipartite- and tripartite-entangled states small register consisting individual 13C nuclei diamond lattice. Individual nuclear spins are controlled via their hyperfine coupling to single electron nitrogen-vacancy defect center. Quantum correlations high quality persist on millisecond time scale even temperature, which adequate sophisticated operations.
Abstract Atomic-sized fluorescent defects in diamond are widely recognized as a promising solid state platform for quantum cryptography and information processing. For these applications, single photon sources with high intensity reproducible fabrication methods required. In this study, we report novel color center diamond, composed of germanium (Ge) vacancy (V) named the GeV center, which has sharp strong photoluminescence band zero-phonon line at 602 nm room temperature. We demonstrate new...
Abstract Solid-state single spins are promising resources for quantum sensing, quantum-information processing and networks, because they compatible with scalable quantum-device engineering. However, the extension of their coherence times proves challenging. Although enrichment spin-zero 12 C 28 Si isotopes drastically reduces spin-bath decoherence in diamond silicon, solid-state environment provides deleterious interactions between electron spin remaining its surrounding. Here we...
The dynamics of single electron and nuclear spins in a diamond lattice with different 13C spin concentration is investigated. It shown that coherent control up to three individual nuclei dense cluster feasible. free induction decays Bell states coherences among are compared analyzed. Reduction decay time T2* coherence T2 upon increase has been found. For material depleted spin, as long 30 microseconds 1.8 ms for the observed. dependence explained by Fermi contact dipolar interactions...
Nitrogen-vacancy (NV) centers in diamond have attracted significant interest because of their excellent spin and optical characteristics for quantum information metrology. To exploit these characteristics, precise control the orientation NV axis lattice is essential. Here we show that more than 99% can be aligned along [111] by chemical vapor deposition homoepitaxial growth on (111) substrates. We also discuss alignment mechanisms. Our result enables a fourfold improvement magnetic field...
We have built a hybrid system composed of superconducting flux qubit (the processor) and an ensemble nitrogen-vacancy centers in diamond memory) that can be directly coupled to one another, demonstrated how information transferred from the memory, stored, subsequently retrieved. established coherence properties memory succeeded creating entangled state between processor demonstrating state's is preserved. Our results are significant step towards using electron spin as quantum for qubits.
Optical illumination on negatively charged nitrogen-vacancy $(\mathrm{N}{\mathrm{V}}^{\ensuremath{-}})$ centers inevitably causes stochastic charge-state transitions between the $\mathrm{N}{\mathrm{V}}^{\ensuremath{-}}$ and neutral charge state of NV center. It limits steady-state population to 5% at minimum (\ensuremath{\sim}610 nm) 80% (\ensuremath{\sim}532 maximum in intrinsic diamond depending wavelength. Here, we show Fermi-level control by phosphorus doping generates 99.4...
A bstract We propose an approach to directly search for light dark matter, such as the axion or photon, by using magnetometry with nitrogen-vacancy centers in diamonds. If matter couples electron spin, it affects evolution of Bloch vectors consisting spin triplet states, which may be detected through several techniques. give concrete examples use dc and ac estimate sensitivity on couplings.
OH stretching vibrations of phenol−(H2O)n clusters (n = 1, 3) in the S1 state have been observed by UV−IR double resonance spectroscopy, where fluorescence dip induced IR excitation was monitored. The spectra were analyzed comparing with those S0 reported a previous work. It found that frequency reduction phenolic vibration and an enhancement interactions among hydrogen bond network cluster much larger than state, representing increase acidity phenol upon electronic excitation. nonradiative...
We report a voltage-induced perpendicular magnetic anisotropy (PMA) change in sputter-deposited Ta|CoFeB|MgO and Ru|CoFeB|MgO junctions. The PMA is quantitatively evaluated by the field dependence of tunneling magnetoresistance for various bias voltages. find that both sign amplitude voltage effect depend on underlayer, Ta or Ru, below CoFeB layer. rf ferromagnetic resonance spectra also support underlayer-material-dependent direction torque. present study shows underlayer one key parameters...
We investigated pulse voltage-induced dynamic magnetization switchings in magnetic tunneling junctions with a high resistance-area product of 2 kΩ μm2. found that bistable switching and the oscillatory behavior probability as function voltage duration are realized at lower current density (−1.1 × 105 A/cm2) than conventional spin-transfer-torque-induced switching. In addition, different strengths confirmed existence torque induced by change perpendicular anisotropy. This can be useful...
The Dzyaloshinskii–Moriya interaction (DMI) is an antisymmetric exchange that plays a decisive role in the formation of chiral magnetic structures and determination magnetoelectric properties. This study investigated impact external voltage on magneto-static surface waves Au/Fe/MgO multilayer. Spin were excited detected using two coplanar waveguides controlled by DC voltage. bias dependence resonant frequency spin revealed effect has both directionally symmetric asymmetric components,...
Use of nitrogen-vacancy (NV) centers in diamond for quantum applications requires fast switching between their two different charge states. Using a diode, scientists now demonstrate the first time deterministic, purely electrical, and room-temperature charge-state control single NV on scale microsecond.
The ${T}_{V2a}$ center, which was suggested to be the excited triplet state $(S=1)$ of neutral silicon vacancy related defect [S\"orman et al., Phys. Rev. B $61,$ 2613 (2000)] in electron-irradiated n-type $4H\ensuremath{-}\mathrm{SiC}$ has been studied by continuous wave and pulsed electron paramagnetic resonance (EPR). spin multiplicity determined quartet $(S=3/2)$ nutation method EPR technique. From temperature dependence signal intensity, it revealed that spectrum is arising from an...
The hybridization of distinct quantum systems has opened new avenues to exploit the best properties these individual systems. Superconducting circuits and electron spin ensembles are one such example. Strong coupling coherent transfer storage information been achieved with nitrogen vacancy centres in diamond. Recently, we have observed a remarkably sharp resonance (~1 MHz) at 2.878 GHz spectrum flux qubit negatively charged diamond hybrid system under zero external magnetic field. This width...
Coherent communication over mesoscale distances is a necessary condition for the application of solid-state spin qubits to scalable quantum information processing. Among other routes under study, one possibility entails generation magnetostatic surface waves (MSSW) dipolarly coupled shallow paramagnetic defects in wide-bandgap semiconductors. As an initial step this direction, here we make use room-temperature MSSWs mediate interaction between microwave field from antenna and...
Temperature sensing with N-$V$ centers using quantum techniques is very promising, and the fundamental limit of sensitivity a high-density ensemble has not yet been revealed. The authors estimate how several noise parameters depend on spin concentration in such system, use those estimates to predict optimal for maximizing temperature sensitivity. identified here much better than previous reports, indicating excellent potential centers.
Recently, ultrashort laser processing has attracted attention for creating nitrogen-vacancy (NV) centers because this method can create single NV in spatially-controlled positions, which is an advantage quantum information devices. On the other hand, high-density a wide region also important sensing sensitivity directly enhanced by increasing number of centers. A recent study demonstrated creation irradiating femtosecond pulses, but created was limited to micrometer size, and technique...
The bisadduct of fullerene (1) having two nitroxide radicals at the trans-3 position was newly synthesized. ground and photoexcited states 1 were studied by continuous-wave pulsed two-dimensional electron paramagnetic resonance spectroscopy. An exchange interaction between evaluated to be much smaller than an isotropic hyperfine splitting, showing a doublet (S = 1/2) character in state. It found from 2D nutation spectrum that state has quintet 2) which is generated via interactions triplet 1) 1/2).
Abstract The structure determination of intrinsic defects in 4H‐SiC, 6H‐SiC, and 3C‐SiC by means EPR is based on measuring the angular dependence 29 Si/ 13 C hyperfine (HF) satellite lines, from which spin densities, sp‐hybrid ratio, p‐orbital direction can be determined over major atoms comprising a defect. In most cases, not only assignment variety due to inequivalent sites ( h ‐ k ‐sites 4H‐SiC) but also identification defect species accomplished through comparison obtained HF parameters...