Article
Chemistry, Physical
A. Watanabe, T. Nishikawa, H. Kato, M. Fujie, M. Fujiwara, T. Makino, S. Yamasaki, E. D. Herbschleb, N. Mizuochi
Summary: The study focuses on the spin and optical properties of NV centers in phosphorus-doped n-type diamond, demonstrating an extension of spin-coherence time, stabilization of charge state, and improvement of creation yield at a depth of approximately 15 nm. The longest T-2 of about 580 μs for shallow NV centers approaches the limit in bulk diamond, limited by the nuclear spins of natural abundant C-13.
Article
Materials Science, Multidisciplinary
Maria Spethmann, Xian-Peng Zhang, Jelena Klinovaja, Daniel Loss
Summary: Superconducting spin qubits, coupled to each other via a superconductor, demonstrate fast controlled phase-flip gates. The effective interaction between these qubits can be adjusted by the superconducting phase difference, the tunnel barrier strength, or the spin-orbit interaction parameters.
Article
Engineering, Electrical & Electronic
Kaisarbek Omirzakhov, Mohamad Hossein Idjadi, Tzu-Yung Huang, S. Alex Breitweiser, David A. A. Hopper, Lee C. C. Bassett, Firooz Aflatouni
Summary: In this paper, an integrated reconfigurable quantum control system is reported, which is used to find electron-spin resonance (ESR) frequency and perform Rabi, Ramsey, and Hahn-echo measurements for a nitrogen-vacancy (NV) center spin qubit in diamond. The chip can be programmed to synthesize an RF signal tunable from 1.6 to 2.6 GHz, which is modulated with a sequence of up to 4098 reconfigurable pulses with a pulse width and pulse-to pulse delay adjustable from 10 ns to 42 ms and 18 ns to 42 ms, respectively, at a resolution of 2.5 ns. The 180-nm CMOS chip is fabricated within a footprint of 3.02 mm(2) and has a power consumption of 80 mW.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Physics, Applied
Hiroshige Deguchi, Tsukasa Hayashi, Hiroya Saito, Yoshiki Nishibayashi, Minori Teramoto, Masanori Fujiwara, Hiroki Morishita, Norikazu Mizuochi, Natsuo Tatsumi
Summary: We have developed a compact and portable measuring instrument using diamond NV centers, which can be powered by a laptop computer's USB 3.0. The portability is achieved by low power consumption of the optics, thanks to the diamond corner cube that enhances the current of the photodiode by 2.1 times compared to planar diamond, and the microwave source that reduced power consumption by 20 dB using a microwave resonator with a λ/4 open stub to magnetically drive the NV center. These results contribute to the social implementation of diamond sensors.
APPLIED PHYSICS EXPRESS
(2023)
Article
Multidisciplinary Sciences
Hang Liang, Man Jiao, Yue Huang, Pei Yu, Xiangyu Ye, Ya Wang, Yijin Xie, Yi-Fu Cai, Xing Rong, Jiangfeng Du
Summary: Laboratory search for exotic interactions is crucial for exploring physics beyond the standard model. We report new experimental constraints on two exotic spin-dependent interactions at the micrometer scale based on ensembles of nitrogen-vacancy (NV) centers in diamond. Our results establish new bounds for these exotic spin interactions at the micrometer scale.
NATIONAL SCIENCE REVIEW
(2023)
Article
Physics, Multidisciplinary
Carlo Cafaro, Paul M. M. Alsing
Summary: In recent years, the interplay among differential geometry, statistical physics, and quantum information science has gained theoretical interest. This paper explicitly analyzes the Bures and Sjoqvist metrics over manifolds of thermal states for specific spin qubit and superconducting flux qubit Hamiltonian models. The two metrics are generally different when departing from the zero-temperature limit, and this discrepancy is discussed in the case of the superconducting flux Hamiltonian model. The presence of nonclassical behavior, quantified by the two metrics in different manners, leads to the difference between the two metrics.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Review
Nanoscience & Nanotechnology
Irfan Siddiqi
Summary: The review explores the major sources of decoherence in superconducting qubits and the trade-offs between simple and complex circuit designs. It also discusses the impact of materials optimization strategies on quantum computing.
NATURE REVIEWS MATERIALS
(2021)
Review
Materials Science, Multidisciplinary
Conal E. Murray
Summary: The progress in quantum computing is driven by understanding qubit-state interactions with the environment, focusing on superconducting qubits and their mechanisms for relaxation and decoherence. Experimental techniques for assessing these mechanisms are highlighted, emphasizing the significance of dielectric loss and interactions with two-level systems. Future research should prioritize mitigating these effects for successful scaling of superconducting quantum computing.
MATERIALS SCIENCE & ENGINEERING R-REPORTS
(2021)
Article
Optics
Ziyan Li, Ning Zhang, Ji Guo, Qiang Guo, Tingting Yu, Mengshi Zhang, Guanxue Wang, Xiumin Gao, Xuedian Zhang
Summary: In this research, the scientific problem of efficiently and rapidly determining the orientation of multiple nitrogen-vacancy centers in a low-concentration diamond is solved using an azimuthally polarized beam array as the incident beam. The position of the beam array is modulated by an optical pen to excite distinctive fluorescence characterizing multiple and different orientations of nitrogen-vacancy centers. The important result is that the orientation of multiple NV centers can be judged in a low concentration diamond layer, except when they are too close within the diffraction limit. Hence, this efficient and rapid method has a good application prospect in quantum information sensing.
Article
Materials Science, Multidisciplinary
Kin On Ho, Man Yin Leung, Yiu Yung Pang, King Cho Wong, Ping Him Ng, Sen Yang
Summary: This study investigates the properties inside polymeric products using a distinctive protocol with the negatively charged nitrogen vacancy center in nanodiamond. By measuring the time dependence of local pressure and strain during the chemical processes, the researchers were able to probe the local shear stress inside the materials in situ. This methodology is applicable to any kind of transparent amorphous solids with stress in the order of MPa and could potentially be applied to nanoscale in situ property studies with better apparatus.
ACS APPLIED POLYMER MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Will Gilbert, Tuomo Tanttu, Wee Han Lim, MengKe Feng, Jonathan Y. Huang, Jesus D. Cifuentes, Santiago Serrano, Philip Y. Mai, Ross C. C. Leon, Christopher C. Escott, Kohei M. Itoh, Nikolay V. Abrosimov, Hans-Joachim Pohl, Michael L. W. Thewalt, Fay E. Hudson, Andrea Morello, Arne Laucht, Chih Hwan Yang, Andre Saraiva, Andrew S. Dzurak
Summary: This study demonstrates fast electrical control of electron spin in silicon quantum dots by exploiting the switchable interaction between spin and orbital motion of electrons without using a micromagnet. By controlling the energy quantization of electrons in nanostructures, the weak effects of the relativistic spin-orbit interaction in silicon are enhanced, leading to a significant increase in Rabi frequency. The achieved coherence time, gate performance, and gate fidelity show the potential for high-performance all-electrical control in scalable silicon quantum computing.
NATURE NANOTECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
Kuljeet Kaur, Theo Sepulcre, Nicolas Roch, Izak Snyman, Serge Florens, Soumya Bera
Summary: Superconducting circuits are developed as a versatile platform for exploring manybody physics, based on nonlinear elements idealized as two-level qubits. However, the intrinsic multilevel structure of superconducting qubits restricts the validity of the spin-boson paradigm. Numerical renormalization group simulations show that the quantum critical point moves out of the physically accessible range in the multilevel regime. Imposing charge discreteness in a simple variational state accounts for these multilevel effects.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Liam Hanlon, Michael Olney-Fraser, Marcus W. Doherty, Lukas Razinkovas
Summary: The nitrogen-vacancy (NV) center in diamond is a highly studied defect with potential applications in quantum metrology and computation in ambient conditions. The ability to read out the spin state of the NV is crucial for its applications, and optical contrast is a key metric for electron spin readout fidelity. We propose a mechanism for high contrast readout using spin-to-charge conversion and electrode manipulation of NV energy levels, which predicts an optical spin contrast of 42% at room temperature and opens up alternative research pathways for the NV.
Article
Physics, Multidisciplinary
Tim Menke, William P. Banner, Thomas R. Bergamaschi, Agustin Di Paolo, Antti Vepsalainen, Steven J. Weber, Roni Winik, Alexander Melville, Bethany M. Niedzielski, Danna Rosenberg, Kyle Serniak, Mollie E. Schwartz, Jonilyn L. Yoder, Alan Aspuru-Guzik, Simon Gustavsson, Jeffrey A. Grover, Cyrus F. Hirjibehedin, Andrew J. Kerman, William D. Oliver
Summary: This study presents a superconducting circuit architecture that enables two-local and three-local interactions between three flux qubits through a designed coupling module. The system Hamiltonian is estimated using multiqubit pulse sequences implementing Ramsey-type interferometry. The three-local interaction can be coherently tuned over several MHz via the coupler flux biases and can also be turned off. This research has significant applications in quantum annealing, analog quantum simulation, and gate-model quantum computation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Zong-Da Zhang, Si-Yu Yin, Li-Cheng Wang, Ying-De Wang, Yun-Fei Li, Zhen-Nan Tian, Qi-Dai Chen
Summary: An array of single NV centers was prepared using the femtosecond laser direct writing method to address the accuracy and consistency issues in static magnetic field detection. The prepared NV centers have fewer defects and good stress uniformity, with an average spatial positioning error of only 0.2 μm. This array enables high accuracy measurement of magnetic field vector and gradient.
Article
Physics, Applied
Kazutoshi Kojima, Shin-ichiro Sato, Takeshi Ohshima, Shin-Ichiro Kuroki
Summary: 4H-SiC epitaxial layers with ultrahigh resistivity of over 10(10) omega cm were grown using a hot wall chemical vapor deposition system with vanadium doping, and the resistivity was found to be dependent on the type of dopant impurities.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Masayuki Tsutsumi, Tatsuya Meguro, Akinori Takeyama, Takeshi Ohshima, Yasunori Tanaka, Shin-Ichiro Kuroki
Summary: Radiation-hardened CMOS image sensors (CIS) with 4H-SiC photosensors and APS-type circuits were developed and demonstrated. The 4H-SiC photodiodes had a dark current of <2 nA/cm(2), and their spectral sensitivity was evaluated from 200 nm to 400 nm. The photosensors showed a maximal quantum efficiency of 63% at 270 nm and high responses to UV light. After exposure to 2 MGy irradiation, the APS-type photosensors still functioned with a dark current of 25 nA/cm(2).
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Multidisciplinary
Daniil M. Lukin, Melissa A. Guidry, Joshua Yang, Misagh Ghezellou, Sattwik Deb Mishra, Hiroshi Abe, Takeshi Ohshima, Jawad Ul-Hassan, Jelena Vuckovic
Summary: This study reports on the integration of near-transform-limited silicon vacancy (VSi) defects into microdisk resonators fabricated in a CMOS-compatible 4H-silicon carbide-on-insulator platform. It demonstrates a single-emitter cooperativity of up to 0.8 and optical superradiance from a pair of color centers coupled to the same cavity mode. The effect of multimode interference on the photon scattering dynamics from this multiemitter cavity quantum electrodynamics system is investigated. These results are crucial for the development of quantum networks in silicon carbide and bridge the classical-quantum photonics gap by uniting optically coherent spin defects with wafer-scalable, state-of-the-art photonics.
Article
Nanoscience & Nanotechnology
Shingo Sotoma, Hiroshi Abe, Yohei Miyanoiri, Takeshi Ohshima, Yoshie Harada
Summary: In this study, methods for controlling the physicochemical properties of SiC nanoparticles were developed, including dispersion, surface coating, functionalization, and selective labeling of biomolecules. A thermal oxidation chemical-etching method was successfully developed to deaggregate and produce a high yield of dispersed, metal-contaminant-free SiC nanoparticles. Additionally, controllable thickness polydopamine and excellent dispersity polyglycerol coatings were demonstrated. Furthermore, a single-pot method was developed for selective labeling of CD44 proteins on cell surfaces through biotin-mediated immunostaining. The methods developed in this study are of great importance for the application of SiC nanoparticles in biomedical research and will greatly accelerate their development and potential applications in bioimaging and biosensing.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Tetta Suzuki, Yuichi Yamazaki, Takashi Taniguchi, Kenji Watanabe, Yusuke Nishiya, Yu-ichiro Matsushita, Kazuya Harii, Yuta Masuyama, Yasuto Hijikata, Takeshi Ohshima
Summary: In this study, two thermal treatment methods were used to successfully generate negatively charged boron vacancies (V (B) (-)) in hexagonal boron nitride with superior spin properties. Both methods improved the signal-to-noise ratio of the optically detected magnetic resonance signal by a factor of 4. Furthermore, the crystal distortion reflected by the zero-field splitting parameter E significantly reduced after irradiation above 650 degrees C. These findings indicate that thermal treatment is an effective method for a V (B) (-) based quantum sensor.
APPLIED PHYSICS EXPRESS
(2023)
Article
Physics, Applied
C. T. -K. Lew, V. K. Sewani, N. Iwamoto, T. Ohshima, J. C. Mccallum, B. C. Johnson
Summary: Spin defects in solid-state sensors are investigated for their magnetic sensitivity, with potential applications in various industries. The study utilizes a silicon carbide pn-junction diode to detect a spin defect ensemble and enhance the baseline sensitivity through the hyperfine-induced spin-mixing effect observed at zero magnetic field. Additional electron-hole pairs are generated through above bandgap optical excitation, and a balanced detection scheme is implemented to reject common-mode noise, achieving an ultimate sensitivity of 30 nT/root Hz. Both techniques greatly enhance the magnetic sensitivity of the device by a total factor of approximately 24, paving the way for sub-nanotesla magnetic field sensitivities with electrical detection.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Tamotsu Okamoto, Fumiya Furumaki, Eiku Sato, Ippei Isogai, Yuji Kurimoto, Yasuki Okuno, Mitsuru Imaizumi, Masafumi Akiyoshi, Takeshi Ohshima
Summary: In this study, the effects of He ion and electron beam irradiation on substrate-type CdTe solar cells for detecting alpha and beta radiation were investigated. The induced current in the CdTe solar cell dosimeter increased proportionally with He ion current, indicating its potential for alpha radiation detection. The induced current in the dosimeter also showed proportionality to electron flux, with sensitivity depending on electron energy. Furthermore, the substrate-type CdTe solar cell dosimeter demonstrated sufficient resistance to electron beam irradiation, with no significant degradation in short-circuit current observed.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Shu Motoki, Shin-ichiro Sato, Seiichi Saiki, Yuta Masuyama, Yuichi Yamazaki, Takeshi Ohshima, Koichi Murata, Hidekazu Tsuchida, Yasuto Hijikata
Summary: In this study, the potential of V-Si(-) defects for magnetic sensors operating at high temperatures was demonstrated, with the resonance frequency of the ground level being independent of temperature, indicating the possibility of calibration-free magnetic sensors in temperature-varying environments. The results also showed a linear relationship between magnetic sensing sensitivity and V-Si(-) concentration.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Tihomir Knezevic, Eva Jelavic, Yuichi Yamazaki, Takeshi Ohshima, Takahiro Makino, Ivana Capan
Summary: In this study, boron-related defects in low-doped n-type 4H-SiC semitransparent Schottky barrier diodes (SBDs) were investigated using minority carrier transient spectroscopy (MCTS). Boron, introduced during chemical vapor deposition (CVD) crystal growth, led to the presence of shallow (B) and deep boron (D-center) defects, with concentrations as high as 1 x 10(15) cm(-3). Despite the higher concentration of boron compared to nitrogen doping, the steady-state electrical characteristics of the n-type 4H-SiC SBDs remained unaffected.
Article
Chemistry, Physical
Robert Bernat, Tihomir Knezevic, Vladimir Radulovic, Luka Snoj, Takahiro Makino, Takeshi Ohshima, Ivana Capan
Summary: We investigated the impact of large-area 4H-SiC Schottky barrier diodes on the radiation response to ionizing particles. Two diode areas, 1 mm x 1 mm and 5 mm x 5 mm, were compared. We utilized (LiF)-Li-6 and (B4C)-B-10 films as thermal neutron converters on top of the diodes. A thermal neutron efficiency of 5.02% was achieved with (LiF)-Li-6, which is among the highest reported efficiencies. Additionally, a temperature-dependent radiation response to alpha particles was presented, with neutron irradiations conducted in a JSI TRIGA dry chamber and an Am-241 wide-area alpha source used for testing.
Article
Physics, Applied
Hiroki Morishita, Naoya Morioka, Testuri Nishikawa, Hajime Yao, Shinobu Onoda, Hiroshi Abe, Takeshi Ohshima, Norikazu Mizuochi
Summary: In this study, positive contrast in photocurrent detected magnetic resonance (PDMR) of nitrogen-vacancy (N-V) centers in diamond is observed. The sign of the PDMR contrast depends on the difference in the photocurrent generated from the excited states and the metastable state of N-V centers. Additionally, noise suppression using a phase-cycling-based noise-canceling technique is introduced to achieve electrically detected ac magnetic field sensing with a sensitivity of 29 nT Hz-1/2.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Multidisciplinary
Islay O. O. Robertson, Sam C. C. Scholten, Priya Singh, Alexander J. J. Healey, Fernando Meneses, Philipp Reineck, Hiroshi Abe, Takeshi Ohshima, Mehran Kianinia, Igor Aharonovich, Jean-Philippe Tetienne
Summary: Detecting magnetic noise from small quantities of paramagnetic spins is achieved using spin defects in hexagonal boron nitride (hBN). Negatively charged boron vacancy defects are created in ultra-thin hBN nanoflakes, and the longitudinal spin relaxation time (T1) is measured. By decorating the dry hBN nanopowder with paramagnetic Gd3+ ions, a clear T1 quenching under ambient conditions is observed, indicating the presence of added magnetic noise. Spin measurements, including T1 relaxometry, can also be performed using solution-suspended hBN nanopowder. These findings demonstrate the potential and versatility of hBN quantum sensors for various sensing applications and pave the way towards a truly 2D, ultrasensitive quantum sensor.
Editorial Material
Physics, Applied
Khalid Hattar, Rudy J. M. Konings, Lorenzo Malerba, Takeshi Ohshima
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
C. t. -k. Lew, V. K. Sewani, T. Ohshima, J. C. McCallum, B. C. Johnson
Summary: Silicon carbide (SiC) power devices are crucial in high voltage electronics, but defects at interfaces and in the bulk affect their reliability and performance. This study presents a charge pumping method to characterize SiC/SiO 2 interface defects in commercial SiC power metal-oxide-semiconductor field-effect transistors (MOSFETs). The method is also used to investigate spin states at the SiC/SiO 2 interface through charge pumping electrically detected magnetic resonance (CP-EDMR).
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
Maria Maffei, Cyril Elouard, Bruno O. Goes, Benjamin Huard, Andrew N. Jordan, Alexia Auffeves
Summary: This study demonstrates that anomalous weak values and Wigner function negativities occur when analyzing the energetics of a single-qubit gate generated by a resonant coherent field traveling in a waveguide. The correlations between the qubit and the field lead to bounds on the gate fidelity and a nontrivial energy balance. The experimental scheme involves continuous monitoring of the field through heterodyne detection and postselection based on the qubit's measurement outcomes.
