Room Temperature Coherent Spin Alignment of Silicon Vacancies in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>4</mml:mn><mml:mi>H</mml:mi></mml:math>- and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>6</mml:mn><mml:mi>H</mml:mi></mml:math>-SiC

We report T 2 spin coherence times for electronic states localized in Si vacancies in 4H-SiC. Our spin coherence study included two SiC samples that were irradiated with 2 MeV protons at different fluences (10 13 and 10 14 cm -2 ) in order to create samples with unique defect concentrations. Using optically detected magnetic resonance and spin echo, the coherence times for each sample were measured across a range of temperatures from 8 K to 295 K. All echo experiments were done at a magnetic field strength of 0.371 T and a microwave frequency of 10.49 GHz. The longest coherence times were obtained at 8 K, being 270 ± 61 µs for the 10 13 cm -2 proton-irradiated sample and 104 ± 17 µs for the 10 14 cm -2 sample. The coherence times for both samples displayed unusual temperature dependences; in particular, they decreased with temperature until 60 K, then increased until 160 K, then decreased again. This increase between 60 and 160 K is tentatively attributed to a motional Jahn-Teller effect. The consistently longer lifetimes for the 10 13 cm -2 sample suggest that a significant source of the spin dephasing can be attributed to dipole-dipole interactions between Si vacancies or with other defects produced by the proton irradiation. The lack of a simple exponential decay for our 10 14 cm -2 sample indicates an inhomogeneous distribution of defect spins.

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“…Each polytype can have a variety of possible defects, and furthermore each defect type may possess unique spin properties [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

et al. 2017

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“…Such single quantum systems have been realized using quantum dots 6 , colour centres in diamond 7 , dopants in nanostructures 8 and molecules 9 . More recently, ensemble emitters with spin dephasing times in the order of microseconds and room-temperature optically detectable magnetic resonance (ODMR) have been identified in silicon carbide (SiC) [10][11][12] , a compound being highly compatible to up-to-date semiconductor device technology. Until recently, however, the engineering of such spin centres in SiC on the single-emitter level has remained elusive 13 .…”

mentioning

confidence: 99%

Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

et al. 2015

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Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption crosssection, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.

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“…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.…”

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confidence: 99%

“…The suppression above 50 K is accompanied by the increase of sample conductivity due to the ionization of nitrogen donors. The conductivity is probably the only limiting factor, as in insulating SiC samples the spin pumping is efficient even at room temperature [11].…”

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confidence: 99%

Resonant Addressing and Manipulation of Silicon Vacancy Qubits in Silicon Carbide

Riedel¹,

Fuchs²,

Kraus³

et al. 2012

Phys. Rev. Lett.

173

154

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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...

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Room Temperature Coherent Spin Alignment of Silicon Vacancies in4H- and6H-SiC

Cited by 122 publications

References 15 publications

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

Electron spin coherence of silicon vacancies in proton-irradiated 4 H -SiC

Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

Resonant Addressing and Manipulation of Silicon Vacancy Qubits in Silicon Carbide

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