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QI: Fachverband Quanteninformation
QI 4: Materials and Devices for Quantum Technology I (joint session HL/QI)
QI 4.5: Vortrag
Montag, 18. März 2024, 16:00–16:15, EW 203
Spin-orbit coupling of color centers for quantum applications — •Mirjam Neubauer, Maximilian Schober, Witold Dobersberger, and Michel Bockstedte — Institute for Theoretical Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria
Color centers in semiconductors, such as the NV-center in diamond, the silicon vacancy (VSi−), and the di-vacancy (VCVSi) in 4H-silicon carbide (4H-SiC), are potential candidates for quantum bits (qubits). Manipulating the spin optically involves exciting the fundamental high-spin multiplet and intersystem crossing (ISC), which includes spin-orbit, spin-spin, and spin-phonon couplings. These interactions, together with the zero-field splitting of ground and excited states, enable diverse spin-photon protocols. To optimize the engineering of such interfaces, a comprehensive understanding of spin-selective interactions and resulting spin-relaxation pathways is crucial. Recent experiments regarding the VSi− in SiC have revealed spin-dependent lifetimes and intercrossing rates using an effective model that considers only one or two out of the five predicted intermediate states [1]. Here we address this issue. We employ our extended CI-cRPA approach for correlated defect states [2] to calculate the spin-orbit and spin-spin coupling. We present a fine structure of the quartet states of VSi− consistent with existing literature. Based on our calculations, we discuss the ISC and spin-relaxation paths.
[1] N. Morioka et al.Phys. Rev. Appl. 17 054005 (2022).
[2] M. Bockstedte, et al., npj Quant Mater 3, 31 (2018).
Keywords: silicon vacancy; qubit; spin relaxation dynamics; ab initio theory; silicon carbide