EPR identification of the triplet ground state and photoinduced population inversion for a Si-C divacancy in silicon carbide

Баранов, П. Г.; Il’in, I. V.; Мохов, Е. Н.; Muzafarova, M. V.; Orlinskiĭ, S. B.; Schmidt, Jan

doi:10.1134/1.2142873

Cited by 81 publications

(69 citation statements)

References 7 publications

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“…The V2 center in 4H -SiC exhibits an observable ODMR signal even at room temperature and its spin ensemble has been used for magnetometry [17][18][19][20]. Thus, improving the brightness and ODMR contrast of these single emitters is promising for room-temperature nanoscale magnetometry of biological molecules and quantum information processing applications [4,10]. For a proper theoretical description and single defect engineering, the actual configuration of this center should be determined.…”

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confidence: 99%

“…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].…”

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

et al. 2017

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“…These forms have been alternatively labeled as PL1-PL4 [5,7], P6=P7 centers (in electron paramagnetic resonance studies) [1,2,28], and the UD2 lines (in PL studies) [12]. Their electronic ground states are spin triplets and described by the Hamiltonian [24,29]:…”

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Electrically and Mechanically Tunable Electron Spins in Silicon Carbide Color Centers

et al. 2014

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The electron spins of semiconductor defects can have complex interactions with their host, particularly in polar materials like SiC where electrical and mechanical variables are intertwined. By combining pulsed spin resonance with ab initio simulations, we show that spin-spin interactions in 4H-SiC neutral divacancies give rise to spin states with a strong Stark effect, sub-10(-6) strain sensitivity, and highly spin-dependent photoluminescence with intensity contrasts of 15%-36%. These results establish SiC color centers as compelling systems for sensing nanoscale electric and strain fields

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“…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).…”

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“…Among its several inequivalent forms, those aligned to the crystal's c axis have the same C 3v symmetry as the nitrogen-vacancy center in diamond. They are the hh and kk divacancies in 4H-SiC [4,5], and the hh, k 1 k 1 , and k 2 k 2 divacancies in 6H-SiC [14,42,43], where the h (hexagonal site) and k (quasicubic site) labels represent the inequivalent lattice sites for vacancies in the SiC lattice. The physical structure of the c-axis-oriented PL6 defect in 4H-SiC [10,14,16] is currently undetermined, but a close relationship to the neutral divacancies is indicated by its similar optical and spin resonances [10], radiative lifetimes [16], and hyperfine spectrum (measured here, see Table I).…”

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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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EPR identification of the triplet ground state and photoinduced population inversion for a Si-C divacancy in silicon carbide

Cited by 81 publications

References 7 publications

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

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

Electrically and Mechanically Tunable Electron Spins in Silicon Carbide Color Centers

Polarizing Nuclear Spins in Silicon Carbide

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