Article
Physics, Applied
I. Lekavicius, S. G. Carter, D. J. Pennachio, S. White, J. R. Hazjus, A. P. Purdy, D. K. Gaskill, A. L. Yeats, R. L. Myers-Ward
Summary: Point defects in solid-state materials, especially diamond's nitrogen-vacancy center, have been widely used for quantum sensing. However, exploring spin defects in other materials, such as silicon carbide, is becoming increasingly important. In this study, the improved sensitivity of a magnetic sensor system utilizing an ensemble of silicon vacancies in silicon carbide is reported, achieving an order of magnitude enhancement compared to previous results.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
I Lekavicius, R. L. Myers-Ward, D. J. Pennachio, J. R. Hajzus, D. K. Gaskill, A. P. Purdy, A. L. Yeats, P. G. Brereton, E. R. Glaser, T. L. Reinecke, S. G. Carter
Summary: In solid-state spin systems, unwanted interactions with surrounding spin baths and inhomogeneity are common challenges. The silicon vacancy in silicon carbide (SiC) can alleviate many of these issues and improve performance through isotopic purification and choosing the basis state in the spin quartet.
Article
Quantum Science & Technology
I. D. Breev, Z. Shang, A. Poshakinskiy, H. Singh, Y. Berencen, M. Hollenbach, S. S. Nagalyuk, E. N. Mokhov, R. A. Babunts, P. G. Baranov, D. Suter, S. A. Tarasenko, G. Astakhov, A. N. Anisimov
Summary: Controllable solid-state spin qubits are important for applied quantum technologies. This study investigates the optical and spin properties of atomic-scale qubits in SiC, and reveals the inverted excited-state fine structure of a specific silicon-vacancy in the 6H-SiC polytype. The study also explores the impact of competing optical spin pumping mechanisms on the spin readout contrast.
NPJ QUANTUM INFORMATION
(2022)
Article
Multidisciplinary Sciences
Jun-Feng Wang, Fei-Fei Yan, Qiang Li, Zheng-Hao Liu, Jin-Ming Cui, Zhao-Di Liu, Adam Gali, Jin-Shi Xu, Chuan-Feng Li, Guang-Can Guo
Summary: The authors use anti-Stokes excitation to detect Si vacancy spins in SiC, achieving a threefold improvement in signal contrast, and show promising applications in quantum information processing and quantum sensing.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Victor A. Soltamov, Boris Yavkin, Andrey N. Anisimov, Harpreet Singh, Anna P. Bundakova, Georgy Mamin, Sergei B. Orlinskii, Evgeniy N. Mokhov, Dieter Suter, Pavel G. Baranov
Summary: The study demonstrates coherent spin manipulations of spin-3/2 color center ensembles in 6H-SiC crystal under high magnetic fields, showing room temperature control and a decrease in relaxation times T-1 and T-2 with increasing temperature and magnetic field strength. The experiments also reveal the potential for optically detecting the spin alignment between M-S = +/- 3/2 in spin-3/2 color centers through optically pumped silent M-S = +/- 1/2 sublevels, including the observation of Rabi oscillations.
Article
Materials Science, Multidisciplinary
Jixing Zhang, Tianzheng Liu, Lixia Xu, Guodong Bian, Pengcheng Fan, Mingxin Li, Chang Xu, Heng Yuan
Summary: This article proposes a scheme for DC nitrogen-vacancy (NV) center magnetometry that combines the advantages of lock-in detection and pulse-type schemes. The proposed pulsed lock-in scheme achieves smaller linewidth, higher contrast, and better sensitivity compared to the conventional continuous-wave lock-in scheme. Experimental results show an improvement by a factor of four in sensitivity and a factor of 60 in the minimum resolvable magnetic field compared to the conventional method.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Automation & Control Systems
Yudi Xiao, Martijn Sebastiaan Duraij, Zhe Zhang, Tiberiu-Gabriel Zsurzsan, Michael A. E. Andersen
Summary: The three-level neutral-point-clamped (TLNPC) dc-dc converter is widely used for high input voltage applications due to its simplicity, high input voltage tolerance, and zero-voltage-switching (ZVS) operation. However, when using a recovery approach in a Silicon Carbide (SiC)-based TLNPC converter, the outer switches experience hard-switching due to the quasi-linear output capacitance of SiC mosfets. A modified design approach is introduced to ensure ZVS of all switches in a full-SiC TLNPC dc-dc converter. Experimental results from a 3 kW full-SiC TLNPC prototype validate the analysis, achieving ZVS in the output power range of 1.2-3 kW with a rated input voltage of 1.2 kV and output voltage of 600 V.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Chemistry, Physical
Qian Zhang, Nannan You, Peng Liu, Jiayi Wang, Yang Xu, Shengkai Wang
Summary: By studying the defect distribution and repair mechanism of microwave plasma oxidation, high quality SiC gate oxide can be achieved with improved dielectric reliability.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Applied
Johannes Engel, Kaushalya Jhuria, Debanjan Polley, Tobias Luehmann, Manuel Kuhrke, Wei Liu, Jeffrey Bokor, Thomas Schenkel, Ralf Wunderlich
Summary: A common technique for creating color centers in wideband gap semiconductors is ion implantation followed by thermal annealing. Typically, this annealing process takes place in a vacuum oven. In this study, we utilized annealing based on femtosecond laser pulses. By implanting fluorine ions at 54 keV and chlorine ions at 74 keV into diamond, and performing micrometer precise annealing using focused femtosecond laser pulses (800 nm +/- (30) nm) with varying pulse numbers and repetition rates, we successfully created shallow spots with color centers of different brightness.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Harpreet Singh, Andrey N. Anisimov, Pavel G. Baranov, Dieter Suter
Summary: This research focuses on the study of charged silicon vacancies in silicon carbide (SiC), specifically in the 6H-SiC polytype. Optically detected magnetic resonance (ODMR) spectra were used to correlate optical and magnetic resonance signals and separate signals from different vacancies. The results also explained the observed temperature-dependent changes in the ODMR signal.
MATERIALS RESEARCH EXPRESS
(2023)
Article
Physics, Multidisciplinary
Yahaya Saadu Itas, Abdussalam Balarabe Suleiman, Chifu E. Ndikilar, Abdullahi Lawal, Razif Razali, Ismail Ibrahim Idowu, Mayeen Uddin Khandaker
Summary: This study investigates the effects of oxygen absorption on two types of single walled silicon carbide nanotubes with different chiral angles. The results show that oxygen absorption closes the band gap, transforming the materials from semiconducting to metallic, indicating potential applications in automobile gas switches for air conditioners and daylight sensors.
Article
Materials Science, Ceramics
Ying Song, Zongwei Xu, Mathias Rommel
Summary: Point defects in silicon carbide can be utilized as color centers for quantum sensing or as carriers to influence electrical performance. Confocal spectroscopic characterization allows the determination of optical and electrical properties without sample preparation, but phenomena such as refraction and aberration can complicate the interpretation of results.
CERAMICS INTERNATIONAL
(2023)
Article
Multidisciplinary Sciences
Dominik M. Irber, Francesco Poggiali, Fei Kong, Michael Kieschnick, Tobias Luehmann, Damian Kwiatkowski, Jan Meijer, Jiangfeng Du, Fazhan Shi, Friedemann Reinhard
Summary: The all-optical spin readout scheme demonstrated in this study achieves single-shot fidelity even with poor photon collection efficiency, which is crucial for sensing and scalable quantum registers based on shallow implanted NV centers.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Yexin Fan, Zongwei Xu, Ying Song, Tianze Sun
Summary: The study utilized molecular dynamics simulations to investigate the mechanism of silicon vacancy defects and damage evolution during hydrogen ion implantation and subsequent annealing, showing that the local temperature generated by hydrogen ion implantation could affect the fluctuation of silicon vacancy defects. Optimizing annealing conditions can improve the yield of silicon vacancy defects, with an optimal annealing temperature.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Joseph Fabre, Philippe Ladoux, Herve Caron, Andrea Verdicchio, Jean-Marc Blaquiere, Didier Flumian, Sebastien Sanchez
Summary: This article discusses the proposal of a new 9 kV dc electrification system in electric railways, focusing on the preparation for infrastructure and rolling stock migration, emphasizing the importance of using efficient power electronic transformers. Through experiments and testing, a compact and high-power isolated dc-dc converter with high efficiency has been successfully achieved.
IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION
(2021)
Article
Physics, Atomic, Molecular & Chemical
S. B. Orlinskii, V. A. Soltamov, G. V. Mamin, O. G. Poluektov, J. Schmidt, P. G. Baranov
Summary: High-frequency ENDOR experiments were conducted to determine the hyperfine interaction between unpaired electrons and nuclear spins, translating into spin density of electronic wave functions. Studies on spatial distribution of wave functions for different crystals and nanostructures were presented. Observations include changes in electronic wave functions and direct reconstructions of shallow electronic centers and self-trapped excitons in certain materials. Additionally, limitations in modeling and successful dynamic nuclear polarization were discussed.
APPLIED MAGNETIC RESONANCE
(2022)
Article
Chemistry, Multidisciplinary
Andreas Sperlich, Michael Auth, Vladimir Dyakonov
Summary: The study shows that ternary organic solar cells using different mixtures of fullerene acceptors exhibit similar performance due to redistribution of electrons to nearby acceptors during the charge transfer step. The reduced Delta LUMO differences in fullerene mixtures explain the shift in open circuit voltage for the organic solar cells. Hybridization leads to an effective fullerene LUMO, making multi-acceptor blends a viable option for photodetectors and solar cells.
ISRAEL JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Fadis F. Murzakhanov, Georgy Vladimirovich Mamin, Sergei Borisovich Orlinskii, Uwe Gerstmann, Wolf Gero Schmidt, Timur Biktagirov, Igor Aharonovich, Andreas Gottscholl, Andreas Sperlich, Vladimir Dyakonov, Victor A. Soltamov
Summary: In this study, we demonstrated the coherent coupling of negatively charged boron vacancies (V-B(-)) with surrounding nuclei in hexagonal boron nitride (hBN), which meets the basic requirements for quantum technology applications. We successfully achieved the readout of the V-B(-) spin coherence using various techniques and showed the characteristics of elongation of coherence time and modulation of Hahn-echo decay. Additionally, the DFT calculation confirmed the confined electron-nuclear coupling in the defective layer.
Article
Quantum Science & Technology
I. D. Breev, Z. Shang, A. Poshakinskiy, H. Singh, Y. Berencen, M. Hollenbach, S. S. Nagalyuk, E. N. Mokhov, R. A. Babunts, P. G. Baranov, D. Suter, S. A. Tarasenko, G. Astakhov, A. N. Anisimov
Summary: Controllable solid-state spin qubits are important for applied quantum technologies. This study investigates the optical and spin properties of atomic-scale qubits in SiC, and reveals the inverted excited-state fine structure of a specific silicon-vacancy in the 6H-SiC polytype. The study also explores the impact of competing optical spin pumping mechanisms on the spin readout contrast.
NPJ QUANTUM INFORMATION
(2022)
Article
Optics
Yulia A. Uspenskaya, Elena Edinach, Alexandr S. Gurin, Roman A. Babunts, Hike R. Asatryan, Nikolai G. Romanov, Pavel G. Baranov
Summary: The spin-dependent optical properties of garnet crystals and ceramics doped with cerium and co-doped with gadolinium and/or terbium were studied using optically detected magnetic resonance. The results showed that the photoluminescence excited by circularly polarized light can be used for selective monitoring of the spin sublevels of cerium ions. The study also revealed the coupling between the gadolinium and cerium spin systems, as well as the presence of non-Kramers terbium centers in yttrium aluminum garnet crystals.
JOURNAL OF LUMINESCENCE
(2022)
Article
Physics, Condensed Matter
F. F. Murzakhanov, I. E. Mumdzhi, G. Mamin, R. Yusupov, V. Yu Davydov, A. N. Smirnov, M. Muzafarova, S. S. Nagalyuk, V. A. Soltamov
Summary: This study investigates the possibility of creating defects with spin-dependent fluorescence in a van der Waals material, hexagonal boron nitride (hBN), by irradiating it with high-energy protons (E-P = 15 MeV). The results from microphotoluminescence and electron paramagnetic resonance methods demonstrate the emergence of boron vacancies in the negatively charged state (V-B(-) centers) following irradiation, with optically induced population inversion in the ground triplet spin state (S = 1).
PHYSICS OF THE SOLID STATE
(2022)
Article
Physics, Applied
R. A. Babunts, A. S. Gurin, E. Edinach, H-J Drouhin, V. Safarov, P. G. Baranov
Summary: Using high-frequency electron paramagnetic resonance (EPR), giant fine structure splitting of non-Kramers ions in β-Ga2O3 crystals was observed, revealing the D-5 state of Fe2+ ions. This interpretation was supported by experimental evidence.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Jeannine Gruene, Giacomo Londi, Alexander J. Gillett, Basil Staehly, Sebastian Lulei, Maria Kotova, Yoann Olivier, Vladimir Dyakonov, Andreas Sperlich
Summary: The development of non-fullerene acceptors (NFAs) in organic photovoltaics (OPV) has led to a significant progress in power conversion efficiencies, reaching nearly 20%. However, triplet states have been found to negatively affect device performance, leading to non-radiative losses and device degradation. A study using various spin-sensitive methods and quantum-chemical calculations identified the presence of triplet excitons in OPV blends, providing insights into the pathways for triplet formation and suggesting potential for improved charge generation to enhance OPV efficiencies.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Patrick Doerflinger, Yong Ding, Valentin Schmid, Melina Armer, Roland C. Turnell-Ritson, Bin Ding, Paul J. Dyson, Mohammad Khaja Nazeeruddin, Vladimir Dyakonov
Summary: This study investigates the effect of a stabilizing additive on the charge carrier mobility and lifetime in triple cation perovskite thin films under thermal stress. The results reveal different conductivity behaviors in two temperature regions and identify two dominant scattering mechanisms. The stabilizing additive limits temperature-activated mobile ions and retards degradation of the perovskite film, leading to improved performance and stability.
Article
Chemistry, Physical
Rik Hooijer, Andreas Weis, Waldemar Kaiser, Alexander Biewald, Patrick Doerflinger, Clement Maheu, Oleksandr Arsatiants, David Helminger, Vladimir Dyakonov, Achim Hartschuh, Edoardo Mosconi, Filippo De Angelis, Thomas Bein
Summary: Silver pnictohalides, as novel perovskite-inspired materials, have gained attention for their high stability, low toxicity, and promising efficiencies. However, research on the silver antimony iodides is lacking due to challenges in synthesis. In this study, the authors successfully prepared Ag-Sb-I thin films using thiourea as an additive and improved their morphology through alloying with copper. The resulting solar cells demonstrated an enhanced power conversion efficiency by reducing undesired side phases. The study also revealed the detrimental role of silver point defects and the beneficial effect of minor amounts of bismuth on the efficiency and stability of the Rudorffite materials.
CHEMISTRY OF MATERIALS
(2023)
Article
Physics, Condensed Matter
A. N. Anisimov, I. D. Breev, K. Likhachev, O. P. Kazarova, S. S. Nagalyuk, P. G. Baranov, B. Ya Ber, D. Yu Kazantcev, M. P. Scheglov, E. N. Mokhov
Summary: This study comprehensively analyzed the process of bulk AlN crystal formation on SiC substrates using various testing methods. The presence of silicon on the surface of the grown AlN crystals and at the SiC/AlN phase boundary was detected. Based on this discovery, a new model for the growth of high-quality bulk AlN crystals on SiC substrates through the formation of a layer of liquid silicon was proposed. The application of this model will facilitate the growth of large, high-quality AlN crystals.
Article
Physics, Multidisciplinary
Harpreet Singh, Mario Alex Hollberg, Andrey N. Anisimov, Pavel G. Baranov, Dieter Suter
Summary: This paper investigates the multi-photon transitions of silicon vacancy driven by a strong RF field in a low magnetic field. By measuring continuous-wave optically detected magnetic resonance spectra and observing the Rabi oscillations and free induction decays, the authors identify the multiple RF photon transitions of different types of silicon vacancy.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Tieshan Yang, Noah Mendelson, Chi Li, Andreas Gottscholl, John Scott, Mehran Kianinia, Vladimir Dyakonov, Milos Toth, Igor Aharonovich
Summary: The use of SiO2 nanopillars enhances the optically detected magnetic resonance (ODMR) contrast of negatively charged boron vacancy (V-B(-)) emission, which can be used in miniaturized quantum sensors in layered heterostructures.