Several systems in the solid state have been suggested as promising candidates for spin-based quantum information processing. In spite of significant progress during the last decade, there is a search for new systems with higher potential [D. DiVincenzo, Nature Mat. 9, 468 (2010)]. We report that silicon vacancy defects in silicon carbide comprise the technological advantages of semiconductor quantum dots and the unique spin properties of the nitrogen-vacancy defects in diamond. Similar to atoms, the silicon vacancy qubits can be controlled under the double radio-optical resonance conditions, allowing for their selective addressing and manipulation. Furthermore, we reveal their long spin memory using pulsed magnetic resonance technique. All these results make silicon vacancy defects in silicon carbide very attractive for quantum applications.PACS numbers: 61.72. Hh, 76.70.Hb, 61.72.jd The double radio-optical resonance in atoms [1] constitutes the basis for a unprecedented level of coherent quantum control. Atomic time standards [2] and multiqubit quantum logic gates [3] are among the most known examples. In the solid state, semiconductor quantum dots (QDs) and the nitrogen-vacancy (NV) defects in diamond, frequently referred to as artificial atoms, are considered as the most promising candidates for quantum information processing [4,5]. Nevertheless, such a high degree of quantum control, as achieved in atoms,has not yet been demonstrated in these systems so far. Therefore, there is a search for quantum systems with even more potential [6].Recently, intrinsic defects in silicon carbide (SiC) have been proposed as eligible candidates for qubits [7,8]. Indeed, they reveal quantum spin coherence even at room temperature [9][10][11]. All of these experiments have been carried out under non-resonant optical excitation where all spins are controlled simultaneously. However, for spinbased information processing it is necessary to perform manipulations of selected spins, while the rest should remain unaffected. This demonstration in SiC is still an outstanding task.The selective spin control can be realized using a resonant optical excitation. As a rule, inhomogeneous broadening is much larger than the natural spectral linewidth, and such resonant addressing can be done on single centers only. To avoid this problem, we applied a special procedure to "freeze" silicon vacancy (V Si ) defects during their growth, allowing to preserve a high homogeneity inherent to Lely crystals. This is confirmed by the extremely sharp optical resonances in our samples. The spectral width of the V Si absorption lines is several µeV (ca. 1 GHz), which comparable with that of a single QD or a single NV center in diamond.We then demonstrate the selective spin initialization and readout by tuning the laser wavelength together with the spin manipulation by means of electron spin resonance (ESR). Such a double radio-optical resonance control indicates that the V Si defects strongly interact with light and are well decoupled from lattice vibr...
We report the realization of the optically induced inverse population of the ground-state spin sublevels of the silicon vacancies (V(Si)) in silicon carbide (SiC) at room temperature. The data show that the probed silicon vacancy spin ensemble can be prepared in a coherent superposition of the spin states. Rabi nutations persist for more than 80 μs. Two opposite schemes of the optical alignment of the populations between the ground-state spin sublevels of the silicon vacancy upon illumination with unpolarized light are realized in 4H- and 6H-SiC at room temperature. These altogether make the silicon vacancy in SiC a very favorable defect for spintronics, quantum information processing, and magnetometry.
The cover picture shows a microfl uidic channel and the magnetochromatic microspheres it generates. From a single-synthesis environment, structural-colored microspheres are synthesized by combining an optofl uidic approach with a magnetic property tuning method. The main image features the dynamic color tuning capability of the method; differently colored microspheres are generated in a single microfl uidic channel, and color can be changed in real-time during the synthesis process. The microspheres are produced with controlled and heterogeneous optical properties. They comprise 1D chain arrangements of magnetic nanoparticles, as shown by the microsphere in the foreground. The magnetic nanoparticles enable the microspheres to have the unique structural color. Orientation-dependent color diffraction of the magnetochromatic microspheres can be utilized to form structural color patterns using a patterned magnet. For more information, please read the Communication "Real-Time Optofl uidic Synthesis of Magnetochromatic Microspheres for Reversible Structural Color Patterning" by S. Kwon and coworkers, beginning on page 1163.The frontispiece features the multistrata nanoparticle-a single-core, fi ve-layered nanostructure. It combines tunable, dual-peak, UV-vis-NIR spectrum extinction characteristics; trimodal imaging contrast; a simple synthesis; and facile surface modifi cation capabilities into a single <60-nm-diameter, multifunctional nanosphere that seeks to relieve current methodological limitations by coupling diagnostics and therapeutics into one single theranostic tool. The image shows a model of the interior, multilayered, metallodielectric structure, including a schematic of the fabrication protocol. For more information, please read the Communication "The Multistrata
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.