Isolated electron spins in silicon carbide with millisecond coherence times

Christle, David J.; Falk, Abram L.; Andrich, Paolo; Klimov, Paul V.; Ul-Hassan, Jawad; Són, Nguyên Tiên; Janzén, Erik; Ohshima, Takeshi; Awschalom, D. D.

doi:10.1038/nmat4144

Cited by 433 publications

(503 citation statements)

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“…Note, when the manuscript was in the reviewing process, we learnt about two papers where the coherent control of single spins in SiC is reported 39,40 . Using a solid immersion lens, a count rate of 4 Â 10 4 c.p.s.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

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

et al. 2015

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“…There are qubits that have long electron spin coherence times [1][2][3][4][5], and some of them have been demonstrated to persist up to room temperature [1,4]. These electron spins can be optically initialized and read out [2,[6][7][8][9], making them very attractive candidates for QIP and related applications [10][11][12].…”

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confidence: 99%

Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide

et al. 2017

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The identification of a microscopic configuration of point defects acting as quantum bits is a key step in the advance of quantum information processing and sensing. Among the numerous candidates, silicon-vacancy related centers in silicon carbide (SiC) have shown remarkable properties owing to their particular spin-3/2 ground and excited states. Although, these centers were observed decades ago, two competing models, the isolated negatively charged silicon vacancy and the complex of negatively charged silicon vacancy and neutral carbon vacancy [Phys. Rev. Lett. 115, 247602 (2015)], are still argued as an origin. By means of high-precision first-principles calculations and high-resolution electron spin resonance measurements, we here unambiguously identify the Si-vacancy related qubits in hexagonal SiC as isolated negatively charged silicon vacancies. Moreover, we identify the Si-vacancy qubit configurations that provide room-temperature optical readout. DOI: 10.1103/PhysRevB.96.161114 Point defects in solids acting as quantum bits (qubits) are a highly promising platform for quantum information processing (QIP) and nanoscale sensor applications where typically their electron spin provides the functional quantum states. There are qubits that have long electron spin coherence times [1][2][3][4][5], and some of them have been demonstrated to persist up to room temperature [1,4]. These electron spins can be optically initialized and read out [2,6-9], making them very attractive candidates for QIP and related applications [10][11][12]. Among these qubits, silicon-vacancy related defects in hexagonal polytypes of SiC, such as 4H -and 6H -SiC, have shown favorable spin properties [13,14], demonstrated even at a single defect level at room temperature [4]. Two and three different silicon-vacancy related centers were observed in 4H -and 6H -SiC, where the corresponding photoluminescence (PL) lines are denoted as V1 and V2, and V1, V2, and V3, [15,16], respectively. The V2 line in 4H -SiC [4] and the V2 and V3 lines in 6H -SiC [13] are sufficiently strong to observe their corresponding electron spin via optically detected magnetic resonance (ODMR) measurements at room temperature. In particular, it has been demonstrated that the V2 color center in 4H -SiC can be used for magnetometer [17][18][19][20] and nanoscale thermometer [21] applications and as a room-temperature maser [14].Today, it is widely accepted that V1-V3 PL lines and T V1 -T V3 electron paramagnetic resonance (EPR) signals in 4H -and 6H -SiC are related to spin-3/2 negatively charged silicon vacancies [22][23][24][25]. On the other hand, the actual microscopic configuration of these vacancy related centers is still debated. The unanswered question is whether these centers are isolated silicon vacancies [V Si difference between the two models is how the observed finite zero-field splitting (ZFS) of the ground-state spin sublevels is explained. In model I, it is assumed that the C 3v symmetric crystal field, allowing nonzero ZFS [26], is strong enough t...

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“…Much like the diamond nitrogen-vacancy center [24,25], these color centers have electronic spin states that can be addressed at either ensemble or single-spin levels [18,19] through optically detected magnetic resonance (ODMR). Moreover, spin coherence times can exceed 1 ms [18], and ODMR can persist up to room temperature [10,11,14,19]. Although the fluctuating nuclear spin bath is a principal source of electronic spin decoherence in these types of systems [26], nuclear spins in SiC are not purely detrimental.…”

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confidence: 99%

“…It is both an industrially important substrate for high-performance electronic devices [1] and a host to several types of vacancy-related paramagnetic color centers with remarkable attributes . Much like the diamond nitrogen-vacancy center [24,25], these color centers have electronic spin states that can be addressed at either ensemble or single-spin levels [18,19] through optically detected magnetic resonance (ODMR). Moreover, spin coherence times can exceed 1 ms [18], and ODMR can persist up to room temperature [10,11,14,19].…”

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Polarizing Nuclear Spins in Silicon Carbide

Cappellaro

2015

Physics

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We demonstrate optically pumped dynamic nuclear polarization of 29 Si nuclear spins that are strongly coupled to paramagnetic color centers in 4H-and 6H-SiC. The 99% AE 1% degree of polarization that we observe at room temperature corresponds to an effective nuclear temperature of 5 μK. By combining ab initio theory with the experimental identification of the color centers' optically excited states, we quantitatively model how the polarization derives from hyperfine-mediated level anticrossings. These results lay a foundation for SiC-based quantum memories, nuclear gyroscopes, and hyperpolarized probes for magnetic resonance imaging. DOI: 10.1103/PhysRevLett.114.247603 PACS numbers: 76.70.Fz, 61.72.jn, 71.55.-i, 76.30.Mi Silicon carbide is a promising material for quantum electronics at the wafer scale. It is both an industrially important substrate for high-performance electronic devices [1] and a host to several types of vacancy-related paramagnetic color centers with remarkable attributes . Much like the diamond nitrogen-vacancy center [24,25], these color centers have electronic spin states that can be addressed at either ensemble or single-spin levels [18,19] through optically detected magnetic resonance (ODMR). Moreover, spin coherence times can exceed 1 ms [18], and ODMR can persist up to room temperature [10,11,14,19]. Although the fluctuating nuclear spin bath is a principal source of electronic spin decoherence in these types of systems [26], nuclear spins in SiC are not purely detrimental. If polarized and controlled, they would be a technologically valuable resource.In this Letter, we show that near-infrared light can nearly completely polarize populations of 29 Si nuclear spins in SiC. In this dynamic nuclear polarization (DNP) [27,28] process, the optically pumped polarization of electron spins bound to either neutral divacancy [4,5,8,10,14] or PL6 [10,14,16] color centers is transferred to proximate nuclei via the hyperfine interaction. Optically polarizing nuclei in SiC is experimentally straightforward, requiring only broadband illumination and a small external magnetic field (300-500 G), with which we tune color-center ensembles to their ground-state (GS) or excited-state (ES) spin-level anticrossings (the GSLAC and ESLAC, respectively). Optically pumping crystals has previously led to roomtemperature DNP in napthalene [29], diamond [30][31][32][33][34][35], and GaNAs [36]. Our results show that room-temperature DNP can be efficiently driven in a material that plays a leading role in the semiconductor industry.We find that SiC color centers can mediate a high degree (>85%) of ESLAC-derived nuclear polarization from at least 5 to 298 K, a surprisingly broad temperature range for this mechanism. This robust DNP could be applied to initialize quantum memories in quantumcommunication technologies, especially since the color centers are telecom-range emitters, with narrow optical linewidths at low temperatures [16,21,37]. Other applications of DNP, including solid-state nuclear gyroscopes [38,39...

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Isolated electron spins in silicon carbide with millisecond coherence times

Abstract: The elimination of defects from SiC has facilitated its move to the forefront of the optoelectronics and power-electronics industries 1

Cited by 433 publications

References 33 publications

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

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

Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide

Polarizing Nuclear Spins in Silicon Carbide

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