Előadó: Thiering Gergő (SZFI)

Az előadás témája: Product Jahn-Teller effect in group-IV – Vacancy color centers in diamond (Publication Prize talk)

Az előadás időpontja: 2021. január 19., kedd, 10.00

Helyszín: videokonferencia, https://letsmeet.wigner.hu/szeminarium


Impurities in diamond is of interest due to their broad range of applicability. Various point defects embedded in diamond are realized as a solid-state quantum bit, bioimaging agent, or ultrasensitive electric or magnetic field sensor. The negative SiV was demonstrated to be indistinguishable single photon source in diamond with addressable electron spin. However, it has a short spin coherence time even at cryogenic temperatures. Recently, it has been found that the neutral SiV as a S=1 system has a long coherence time and is very promising for quantum communication applications [1]. However, the electronic structure of SiV(0) is not yet completely understood. In our work [2], we employ plane-wave supercell calculations on SiV(0) with density functional theory methods and beyond, then compare the results with the experimental data. Initially, the 1.31 eV ZPL was erroneously assigned to a 3A2g↔3A1u transition [3]. However, recent uniaxial stress measurements revealed [4] that the ZPL itself is a 3A2g↔3Eu transition and there is an optically inactive 3A2u state below the 3Eu excited state by 6.7 meV. Our present model agrees well with this result and provides a physical background for these findings. In summary, we provide a model for SiV(0) center and predict the properties of GeV(0), SnV(0), PbV(0) centers that might be also interesting qubit candidates if successfully embedded in diamond [5,6].
[1] R. C. Brendon, et al., Science 361, 6397 (2018)
[2] G. Thiering, A. Gali, npj Computational Materials 5(1), 18 (2019)
[3] U. F. S. D'Haenens-Johansson et al., Phys. Rev. B 84, 245208 (2011)
[4] B. L. Green et al., Phys. Rev. B 99, 161112(R) (2019)
[5] Ciccarino, Christopher J. et al., npj Quantum Materials 5.1 (2020): 1-6
[6] Z. Zi-Huai, Paul Stevenson, G. Thiering, ... N. P. de Leon, preprint arXiv:2004.12544 (2020)