| 1. |
- Morioka, Naoya, et al.
(författare)
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Spin-Optical Dynamics and Quantum Efficiency of a Single V1 Center in Silicon Carbide
- 2022
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Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 17:5
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Tidskriftsartikel (refereegranskat)abstract
- Color centers in silicon carbide are emerging candidates for distributed spin-based quantum applications due to the scalability of host materials and the demonstration of integration into nanophotonic resonators. Recently, silicon vacancy centers in silicon carbide have been identified as a promising system with excellent spin and optical properties. Here, we fully study the spin-optical dynamics of the single silicon vacancy center at hexagonal lattice sites, namely V1, in 4H-polytype silicon carbide. By utilizing resonant and above-resonant sublifetime pulsed excitation, we determine spin-dependent excited-state lifetimes and intersystem-crossing rates. Our approach to inferring the intersystem-crossing rates is based on all-optical pulsed initialization and readout scheme, and is applicable to spin-active color centers with similar dynamics models. In addition, the optical transition dipole strength and the quantum efficiency of V1 defect are evaluated based on coherent optical Rabi measurement and local-field calibration employing electric field simulation. The measured rates well explain the results of spin-state polarization dynamics, and we further discuss the altered photoemission dynamics in resonant enhancement structures such as radiative lifetime shortening and Purcell enhancement. By providing a thorough description of the V1 center???s spin-optical dynamics, our work provides deep understanding of the system, which guides implementations of scalable quantum applications based on silicon vacancy centers in silicon carbide.
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| 2. |
- Nagy, Roland, et al.
(författare)
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Quantum Properties of Dichroic Silicon Vacancies in Silicon Carbide
- 2018
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Ingår i: Physical Review Applied. - 2331-7019. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Although various defect centers have displayed promise as either quantum sensors, single photon emitters, or light-matter interfaces, the search for an ideal defect with multifunctional ability remains open. In this spirit, we study the dichroic silicon vacancies in silicon carbide that feature two well-distinguishable zero-phonon lines and analyze the quantum properties in their optical emission and spin control. We demonstrate that this center combines 40% optical emission into the zero-phonon lines showing the contrasting difference in optical properties with varying temperature and polarization, and a 100% increase in the fluorescence intensity upon the spin resonance, and long spin coherence time of their spin-3/2 ground states up to 0.6 ms. These results single out this defect center as a promising system for spin-based quantum technologies.
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| 3. |
- Niethammer, Matthias, et al.
(författare)
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Vector Magnetometry Using Silicon Vacancies in 4H-SiC Under Ambient Conditions
- 2016
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Ingår i: PHYSICAL REVIEW APPLIED. - : AMER PHYSICAL SOC. - 2331-7019. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- 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 = 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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| 4. |
- Udvarhelyi, Peter, et al.
(författare)
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Vibronic States and Their Effect on the Temperature and Strain Dependence of Silicon-Vacancy Qubits in 4H-SiC
- 2020
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Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Silicon-vacancy qubits in silicon carbide (SiC) are emerging tools in quantum-technology applications due to their excellent optical and spin properties. In this paper, we explore the effect of temperature and strain on these properties by focusing on the two silicon-vacancy qubits, V1 and V2, in 4H-SiC. We apply density-functional theory beyond the Born-Oppenheimer approximation to describe the temperature-dependent mixing of electronic excited states assisted by phonons. We obtain a polaronic gap of around 5 and 22 meV for the V1 and V2 centers, respectively, which results in a significant difference in the temperature-dependent dephasing and zero-field splitting of the excited states, which explains recent experimental findings. We also compute how crystal deformations affect the zero-phonon line of these emitters. Our predictions are important ingredients in any quantum applications of these qubits sensitive to these effects.
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