Spin polarization through intersystem crossing in the silicon vacancy of silicon carbide

Dong, Wenzheng; Doherty, Marcus W.; Economou, S. E.

doi:10.1103/physrevb.99.184102

Cited by 28 publications

(19 citation statements)

References 39 publications

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“…However, spin-flip processes can still be mediated by non-radiative intersystem crossing involving metastable states, which allows e.g. for deterministic spin state initialisation 21,24 . Note that we do not consider the system's second excited state, V1', whose fluorescence at 858 nm is strongly reduced at cryogenic temperatures due to ultrafast relaxation to the V1 state 20 .…”

Section: Resultsmentioning

confidence: 99%

Spin-controlled generation of indistinguishable and distinguishable photons from silicon vacancy centres in silicon carbide

et al. 2020

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Quantum systems combining indistinguishable photon generation and spin-based quantum information processing are essential for remote quantum applications and networking. However, identification of suitable systems in scalable platforms remains a challenge. Here, we investigate the silicon vacancy centre in silicon carbide and demonstrate controlled emission of indistinguishable and distinguishable photons via coherent spin manipulation. Using strong off-resonant excitation and collecting zero-phonon line photons, we show a two-photon interference contrast close to 90% in Hong-Ou-Mandel type experiments. Further, we exploit the system's intimate spin-photon relation to spin-control the colour and indistinguishability of consecutively emitted photons. Our results provide a deep insight into the system's spin-phonon-photon physics and underline the potential of the industrially compatible silicon carbide platform for measurement-based entanglement distribution and photonic cluster state generation. Additional coupling to quantum registers based on individual nuclear spins would further allow for high-level network-relevant quantum information processing, such as error correction and entanglement purification.

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Section: Resultsmentioning

confidence: 99%

Spin-controlled generation of indistinguishable and distinguishable photons from silicon vacancy centres in silicon carbide

et al. 2020

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“…This is an indication that both spin states couple to phonons in the same way. A possible explanation is weak spin-orbit coupling [55], but a theoretical consideration of the spin polarization through intersystem crossing [56] involving local vibronic states is necessary to confirm this. Next, we analyze how the change in the V2 PL emission induced by the MW depends on the detection wavelength.…”

Section: Methodsmentioning

confidence: 99%

Local vibrational modes of Si vacancy spin qubits in SiC

et al. 2020

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Silicon carbide is a very promising platform for quantum applications because of the extraordinary spin and optical properties of point defects in this technologically friendly material. These properties are strongly influenced by crystal vibrations, but the exact relationship between them and the behavior of spin qubits is not fully investigated. We uncover the local vibrational modes of the Si vacancy spin qubits in as-grown 4H-SiC. We apply microwave-assisted spectroscopy to isolate the contribution from one particular type of defects, the so-called V2 center, and observe the zero-phonon line together with seven equally separated phonon replicas. Furthermore, we present first-principles calculations of the photoluminescence line shape, which are in excellent agreement with our experimental data. To boost up the calculation accuracy and decrease the computation time, we extract the force constants using machine-learning algorithms. This allows us to identify the dominant modes in the lattice vibrations coupled to an excited electron during optical emission in the Si vacancy. A resonance phonon energy of 36 meV and a Debye-Waller factor of about 6% are obtained. We establish experimentally that the activation energy of the optically induced spin polarization is given by the local vibrational energy. Our findings give insight into the coupling of electronic states to vibrational modes in SiC spin qubits, which is essential to predict their spin, optical, mechanical, and thermal properties. The approach described can be applied to a large variety of spin defects with spectrally overlapped contributions in SiC as well as in other threeand two-dimensional materials.

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“…1). A possible reason is that for non-resonant excitation the V3 centers reside in the 4 A 2 state for some time during the excitation-relaxation cycle [42]. Note that the ESLACs in the 4 E octuplet are expected at much higher magnetic fields than those used in our experiments.…”

Section: Temperature Dependence Of Spin Properties a Excited-state Le...mentioning

confidence: 87%

Inverted fine structure of a 6H-SiC qubit enabling robust spin-photon interface

D.¹,

Shang²,

Poshakinskiy³

et al. 2021

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Spin polarization through intersystem crossing in the silicon vacancy of silicon carbide

Cited by 28 publications

References 39 publications

Spin-controlled generation of indistinguishable and distinguishable photons from silicon vacancy centres in silicon carbide

Spin-controlled generation of indistinguishable and distinguishable photons from silicon vacancy centres in silicon carbide

Local vibrational modes of Si vacancy spin qubits in SiC

Inverted fine structure of a 6H-SiC qubit enabling robust spin-photon interface

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