Understanding the spin-selective transitions of color center for quantum applications by ab initio theory
Sprache des Vortragstitels:
Deutsch
Englischer Vortragstitel:
Understanding the spin-selective transitions of color center for quantum applications by ab initio theory
Englischer Tagungstitel:
Defect in Solids for Quantum Technology
Englische Kurzfassung:
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 multiplets and intersystem crossing (ISC), mediated by spin orbit, spin-spin, and spin-phonon couplings. These interactions, together with the zero field splitting of ground and excited states, enable various spin-photon protocols. For
optimal engineering of such interfaces, a comprehensive understanding of spin selective interactions and resulting spin-relaxation pathways is pivotal. Recent
experiments regarding the VSi
?
in 4H-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 doublet states [1]. Here we address this issue. We employ
our extended CI-cRPA embedding approach for correlated defect states [2] to calculate
the relevant spin-coupling parameters. 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. In particular, we calculate ISC-rates for the two spin
components that are in agreement with the experimental findings [1]. The calculated
rates provide insight into the underlying role of the different intermediate states and
indicate handles for engineering approaches.
[1] N. Morioka, et al., Phys. Rev. Appl. 17 054005 (2022).
[2] M. Bockstedte, et al., npj Quant Mater 3, 31 (2018)
Forschungs-