ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarThiering GergőWigner RCP SZFIProduct Jahn-Teller effect in 
group-IV – Vacancy color centers in diamond (Publication Prize talk)Tuesday, 
19 January 2021, 10:00, video conference, 
https://letsmeet.wigner.hu/szeminariumImpurities 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].Reference[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) Minden érdeklődőt szívesen látunk! - Everyone is 
welcome to attend.Róbert Juhászsem-admin AT szfki.hu