Optical properties and Zeeman spectroscopy of niobium in silicon carbide

Gällström, Andreas; Magnusson, Björn; Kordina, Olof; Són, Nguyên Tiên; Ivády, Viktor; Gali, Ádám; Abrikosov, Igor A.; Janzén, Erik; Ivanov, Ivan Gueorguiev

doi:10.1103/physrevb.92.075207

Cited by 9 publications

(5 citation statements)

References 30 publications

(60 reference statements)

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“…Interestingly, niobium defects have been shown to grow in this ASV configuration 52 , indicating there indeed exist large varieties in the crystal symmetries involved with transition metal defects in SiC. This defect displays S = 1/2 spin with several optical transitions between 892 − 897 nm in 4H-SiC and 907 − 911 nm in 6H-SiC 52 .…”

Section: Further Discussionmentioning

confidence: 96%

Identification and tunable optical coherent control of transition-metal spins in silicon carbide

et al. 2018

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Color centers in wide-bandgap semiconductors are attractive systems for quantum technologies since they can combine long-coherent electronic spin and bright optical properties. Several suitable centers have been identified, most famously the nitrogen-vacancy defect in diamond. However, integration in communication technology is hindered by the fact that their optical transitions lie outside telecom wavelength bands. Several transition-metal impurities in silicon carbide do emit at and near telecom wavelengths, but knowledge about their spin and optical properties is incomplete.We present all-optical identification and coherent control of molybdenum-impurity spins in silicon carbide with transitions at near-infrared wavelengths. Our results identify spin S = 1/2 for both the electronic ground and excited state, with highly anisotropic spin properties that we apply for implementing optical control of ground-state spin coherence. Our results show optical lifetimes of ∼60 ns and inhomogeneous spin dephasing times of ∼0.3 µs, establishing relevance for quantum spin-photon interfacing.2 Electronic spins of lattice defects in wide-bandgap semiconductors have come forward as an important platform for quantum technologies 1 , in particular for applications that require both manipulation of long-coherent spin and spin-photon interfacing via bright optical transitions. In recent years this field showed strong development, with demonstrations of distribution and storage of non-local entanglement in networks for quantum communication 2-6 , and quantum-enhanced field-sensing 7-11 . The nitrogen-vacancy defect in diamond is the material system that is most widely used 12,13 and best characterized 14-16 for these applications.However, its zero-phonon-line (ZPL) transition wavelength (637 nm) is not optimal for integration in standard telecom technology, which uses near-infrared wavelength bands where losses in optical fibers are minimal. A workaround could be to convert photon energies between the emitter-resonance and telecom values 17-19 , but optimizing these processes is very challenging.This situation has been driving a search for similar lattice defects that do combine favorable spin properties with bright emission directly at telecom wavelength. It was shown that both diamond and silicon carbide (SiC) can host many other spin-active color centers that could have suitable properties 20-23 (where SiC is also an attractive material for its established position in the semiconductor device industry 24,25 ). However, for many of these color centers detailed knowledge about the spin and optical properties is lacking. In SiC the divacancy 26-28 and silicon vacancy 10,29-31 were recently explored, and these indeed show millisecond homogeneous spin coherence times with bright ZPL transitions closer to the telecom band.We present here a study of transition-metal impurity defects in SiC, which exist in great variety [32][33][34][35][36][37] . There is at least one case (the vanadium impurity) that has ZPL transitions at telecom wavel...

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Section: Further Discussionmentioning

confidence: 96%

Identification and tunable optical coherent control of transition-metal spins in silicon carbide

et al. 2018

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“…Therefore, we assign this energy threshold to the optical transition from the (-|0) level of the Nb Si V C center to the conduction band minimum. This energy threshold is close to the energy of the zero-phonon line of Nb-related photoluminescence center (~1.36 eV) in 6H-SiC [17]. This optical transition includes a possible Franck-Condon shift and can be slightly larger than the thermal ionization energy of the (-|0) acceptor level of Nb.…”

Section: Resultsmentioning

confidence: 51%

Electron Paramagnetic Resonance Studies of Nb in 6H-SiC

Trinh

Gällström

Són

et al. 2013

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Defects in unintentionally Nb-doped 6H-SiC grown by high-temperature chemical vapor deposition were studied by electron paramagnetic resonance (EPR). An EPR spectrum with a hyperfine (hf) structure consisting of ten equal-intensity lines was observed. The hf structure is identified to be due to the hf interaction between an electron spin S=1/2 and a nuclear spin of 93Nb. The hf interaction due to the interaction three nearest Si neighbors was also observed, suggesting the involvement of the C vacancy (VC) in the defect. Only one EPR spectrum was observed in 6H-SiC polytype. The obtained spin-Hamiltonian parameters are similar to that of the Nb-related EPR defect in 4H-SiC, suggesting that the EPR center in 6H-SiC is the NbSiVC complex in the neutral charge state, NbSiVC0. Photoexcitation EPR experiments suggest that the single negative charge state of the NbSiVC complex is located at ~1.3 eV below the conduction band minimum.

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“…For instance, if Nb − binds a hole in the Coulomb potential of the negatively-charged defect [denoted (Nb − ,h)], then the electron is bound strongly, while the weakly bound hole can be considered as effective-mass like, and vice versa for its antimorph (Nb + ,e), where e denotes now the weakly-bound electron. However, simple energy arguments show [3] that the former possibility (Nb − ,h) is by far the most energetically favourable one and we choose it as a base for our model.…”

Section: Experimental Results Model and Comparison With Experimentsmentioning

confidence: 99%

“…(The relation of the Nbline in Fig. 1 to incorporation of Nb was demonstrated in a doping experiment on 4H-SiC described elsewhere [3].) The PL spectra are excited either using the multiline UV emission of an Ar + ion laser (351 -364 nm), or a wavelength of ~750 nm from a Ti-sapphire laser [the latter laser was utilized also as a tuning source for measuring the PL excitation (PLE) spectra)].…”

Section: Methodsmentioning

confidence: 99%

Optical Properties of the Niobium Centre in 4H, 6H, and 15R SiC

Ivanov

Gällström

Kordina

et al. 2013

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A set of lines in the photoluminescence spectra of 4H-, 6H-, and 15R-SiC in the near-infrared are attributed to Nb-related defects on the ground of doping experiments conducted with 4H-SiC. A model based on a an exciton bound at the Nb-centre in an asymmetric split vacancy configuration at a hexagonal site is proposed, which explains the structure of the luminescence spectrum and the observed Zeeman splitting of the lines.

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Optical properties and Zeeman spectroscopy of niobium in silicon carbide

Cited by 9 publications

References 30 publications

Identification and tunable optical coherent control of transition-metal spins in silicon carbide

Identification and tunable optical coherent control of transition-metal spins in silicon carbide

Electron Paramagnetic Resonance Studies of Nb in 6H-SiC

Optical Properties of the Niobium Centre in 4H, 6H, and 15R SiC

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