Silicon vacancy center in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>4</mml:mn><mml:mi>H</mml:mi></mml:mrow></mml:math>-SiC: Electronic structure and spin-photon interfaces

Soykal, Ö. O.; Dev, Pratibha; Economou, Sophia E.

doi:10.1103/physrevb.93.081207

Cited by 106 publications

(137 citation statements)

References 47 publications

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“…In agreement with previous theoretical estimates [28], these results disprove the existence of an undistorted T d symmetric silicon vacancy [22] in 4H -SiC, which was one of the basic assumptions of model II [14]. Furthermore, both the calculated ZPL energies and the hyperfine values are in good agreement with the experimental data.…”

supporting

confidence: 80%

“…The multiplet structure of these defects includes a 4 A 2 ground state, low-energy 4 A 2 and 4 E optically allowed excited states, and other spin-1/2 shelving states between the ground and optical excited states [28]. Accordingly, in our first-principles calculations, we consider the 4 A 2 ground state and the lowest-energy optically excited state, either the 4 A 2 or the 4 E state.…”

mentioning

confidence: 99%

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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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supporting

confidence: 80%

mentioning

confidence: 99%

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

et al. 2017

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“…The most important difference is that in its stable configuration it involves five active electrons (or, equivalently, three holes). Moreover, the distance of the carbon located along the C 3 -symmetry axis from the vacancy, as calculated with DFT [26], is approximately equal to the distances of the basal carbons from the vacancy. As a result, the C 3v symmetry of this defect is in fact very close to T d in the 4H and 6H polytypes [27,26], and is exactly T d in 3C SiC.…”

Section: Silicon Monovacancymentioning

confidence: 97%

Spin-photon entanglement interfaces in silicon carbide defect centers

Economou

Dev

2016

Nanotechnology

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Abstract. Optically active spins in solid-state systems can be engineered to emit photons that are entangled with the spin in the solid. This allows for applications such as quantum communications, quantum key distribution, and distributed quantum computing. Recently, there has been a strong interest in silicon carbide defects, as they emit very close to the telecommunication wavelength, making them excellent candidates for long range quantum communications. In this work we develop explicit schemes for spin-photon entanglement in several SiC defects: the silicon monovacancy, the silicon divacancy, and the NV center in SiC. Distinct approaches are given for (i) single-photon and spin entanglement and (ii) the generation of long strings of entangled photons. The latter are known as cluster states and comprise a resource for measurement-based quantum information processing.

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“…1(a). It has been suggested that optical excitation leads to spin polarization into the M S ¼ AE1=2 spin sublevels of the ground state due to spin-dependent intersystem crossing [19,32,[46][47][48][49]. The fluorescence emission is brighter when the system is in one of the M S ¼ AE3=2 states which is the basis for optical detection of electron spin resonance [19,46].…”

Section: Electron Spin Resonance Of Silicon Vacancy In Silicon Camentioning

confidence: 99%

Vector Magnetometry Using Silicon Vacancies in4H-SiC Under Ambient Conditions

et al. 2016

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Point defects in solids promise precise measurements of various quantities. Especially magnetic field sensing using the spin of point defects has been of great interest recently. When optical readout of spin states is used, point defects achieve optical magnetic imaging with high spatial resolution at ambient conditions. Here, we demonstrate that genuine optical vector magnetometry can be realized using the silicon vacancy in SiC, which has an uncommon S ¼ 3=2 spin. To this end, we develop and experimentally test sensing protocols based on a reference field approach combined with multifrequency spin excitation. Our work suggests that the silicon vacancy in an industry-friendly platform, SiC, has the potential for various magnetometry applications under ambient conditions.

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Silicon vacancy center in4H-SiC: Electronic structure and spin-photon interfaces

Cited by 106 publications

References 47 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

Spin-photon entanglement interfaces in silicon carbide defect centers

Vector Magnetometry Using Silicon Vacancies in4H-SiC Under Ambient Conditions

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