Silicon-Vacancy Centre

The Silicon-Vacancy Centre (SiV) is an optically active defect in diamond (referred to as a colour centre) that is receiving an increasing amount of interest in the diamond research community. This interest is driven primarily by the coherent optical properties of the SiV, especially compared to the well-known and extensively-studied nitrogen vacancy centre (NV).

Properties of the SiV

Crystallographic

The SiV centre is formed by the replacement of two neighboring carbon atoms from the diamond lattice along the crystallographic <111> direction with vacancies (empty sites) and a silicon atom located in between the two vacant lattice sites. This configuration has D3d point group symmetry.

Electronic

The SiV centre is a single-hole (spin-1/2) system with ground and excited electronic states localized to the diamond bandgap. Each of the ground and excited electronic states has two orbital states split by spin–orbit coupling. Each of these spin–orbit states is doubly spin-degenerate. Strain in the diamond lattice can further increase the splitting between these orbital states. Phonons in the diamond lattice drive transitions between these orbital states, causing rapid equilibration of the orbital population at temperatures above around 1 K.[1]

All four transitions between the two ground and two excited orbital states are dipole allowed with a sharp zero-phonon line (ZPL) at 738 nm (1.68 eV)[2] and minimal phononic sideband in a roughly 20 nm window around 766 nm.[3] The SiV emits much more of its emission into its ZPL, approximately 70% (Debye–Waller factor of 0.7), which is in stark contrast to the 4% Debye–Waller factor of the nitrogen-vacancy centre.[4] The SiV centre also has higher excited states that relax quickly to the lowest excited states, allowing off-resonant excitation.

Because the SiV centre has inversion symmetry, it has no static electric dipole moment to lowest order and is hence immune to Stark shifts from electric field noise within the diamond lattice. As a result, SiV centres typically have optical transition linewidths on the order of the lifetime (Fourier) limit. Moreover, it is possible to find SiV centers with identical optical transition frequencies. [5] These properties (high brightness, narrow optical transitions, and ease of finding indistinguishable emitters) make the SiV centre appealing for applications in solid-state quantum optics.

Spin

The spin properties of the SiV centre remain an active area of research. Although the optical transitions of the SiV centre are spin-preserving, the rapid phonon-induced mixing between the SiV orbital states causes decoherence of the electronic spin. Recent work indicates the possibility of using the 29Si nuclear spin of the SiV as a qubit for quantum information applications.[6][7]

References

  1. ↑ Jahnke, K. D.; Sipahigil, A.; Binder, J. M.; Doherty, M. W.; Metsch, M.; Rogers, L. J.; Manson, N. B.; Lukin, M. D.; Jelezko, F. (April 2015). "Electron–phonon processes of the silicon-vacancy centre in diamond". New Journal of Physics 17. doi:10.1088/1367-2630/17/4/043011.
  2. ↑ Feng, T.; Schwartz, B. D. (1993). "Characteristics and origin of the 1.681 eV luminescence centre in chemical-vapor-deposited diamond films". Journal of Applied Physics 73 (3): 1415. doi:10.1063/1.353239.
  3. ↑ Dietrich, A.; Jahnke, K. D.; Binder, J. M.; Teraji, T.; Isoya, J.; Rogers, L. J.; Jelezko, F. (2014). "Isotopically varying spectral features of silicon-vacancy in diamond". New Journal of Physics 16 (11): 113019. doi:10.1088/1367-2630/16/11/113019.
  4. ↑ Aharonovich, I.; Castelletto, S.; Simpson, D. A.; Su, C. -H.; Greentree, A. D.; Prawer, S. (2011). "Diamond-based single-photon emitters". Reports on Progress in Physics 74 (7): 076501. doi:10.1088/0034-4885/74/7/076501.
  5. ↑ Rogers, L. J.; Jahnke, K. D.; Teraji, T.; Marseglia, L.; Müller, C.; Naydenov, B.; Schauffert, H.; Kranz, C.; Isoya, J.; McGuinness, L. P.; Jelezko, F. (2014). "Multiple intrinsically identical single-photon emitters in the solid state". Nature Communications 5. doi:10.1038/ncomms5739.
  6. ↑ Rogers, L. J.; Jahnke, K. D.; Metsch, M. H.; Sipahigil, A.; Binder, J. M.; Teraji, T.; Sumiya, H.; Isoya, J.; Lukin, M. D.; Hemmer, P.; Jelezko, F. (2014). "All-Optical Initialization, Readout, and Coherent Preparation of Single Silicon-Vacancy Spins in Diamond". Physical Review Letters 113 (26). doi:10.1103/PhysRevLett.113.263602.
  7. ↑ Pingault, B.; Becker, J. N.; Schulte, C. H.  H.; Arend, C.; Hepp, C.; Godde, T.; Tartakovskii, A. I.; Markham, M.; Becher, C.; Atatüre, M. (2014). "All-Optical Formation of Coherent Dark States of Silicon-Vacancy Spins in Diamond". Physical Review Letters 113 (26). doi:10.1103/PhysRevLett.113.263601.
This article is issued from Wikipedia - version of the Wednesday, January 27, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.