Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Focused Session: Frontiers of Electronic Structure Theory 2 (jointly with HL and O)
TT 22.1: Vortrag
Montag, 11. März 2013, 16:00–16:15, H36
Excited States of the divacancy in SiC — •Michel Bockstedte1, Thomas Garratt1, and Adam Gali2 — 1Theoretische Festkörperphysik, FAU Erlangen-Nürnberg, Staudstr. 7B2, D-91058 Erlangen — 2Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest 1525, Hungary
The negatively charged nitrogen-vacancy center in diamond has emerged as a candidate for the implementation of a qbit in quantum computing. Silicon Carbide also fullfils necessary conditions1 which makes it a suitable material for this purpose. With the neutral divacancy it possess a defect center with a high spin ground state, which can be manipulated by spin-resonance techniques.2 Optical excitation of the triplet ground state and subsequent spin-selective recombination via yet unknown intermediate spin-singlet states enables spin-initialization with Mz=0, which is requisit for a qbit. Here we investigate the excitation spectrum of the divacancy based ab initio methods. DFT and TD-DFT calculations3 reveal a Jahn-Teller effect for the first excited triplet state that is absent for the NV-complex. TD-DFT and an ab initio many body hamiltonian nicely reproduce the prominent photoluminescence transitions. The latter method also describes the spin-singlet states. We discuss the defect excitation spectrum in the light of the Jahn-Teller distortion.
[1] J. R. Weber et al., PNAS 107, 8513 (2010).
[2] F. Koehl et al., Nature 479, 84 (2011).
[3] A. Gali, phys. status solidi (b) 248, 1337 (2011).