Understanding the spin-selective transitions of defect spins b ab initio theory of spin-spin and spin-orbit coupling
Sprache des Vortragstitels:
Deutsch
Englischer Vortragstitel:
Understanding the spin-selective transitions of defect spins b ab initio theory of spin-spin
Englischer Tagungstitel:
APS Marchmeeting 2024
Englische Kurzfassung:
Color centers in semiconductors with coupled spins, such as the
NV center in diamond, the silicon vacancy (VSi), and the di vacancy (VCVSi) in silicon carbide (SiC), implement quantum
bits for sensing and other quantum applications. Optical
manipulation of the spin includes the excitation of the
fundamental high-spin transition and spin-selective non-radiative relaxation via intermediate low-spin states facilitated by
spin-spin and spin-orbit coupling. This and the zero-field splittings of the ground and excited states permit a variety of
spin-photon protocols. Optimal engineering of such interfaces
requires a deep understand the different spin-selective
couplings and the resulting spin-relaxation paths. In the case of
the silicon vacancy in SiC, recent experiments obtained spin dependent lifetimes and intercrossing rates based on an
effective model with only one intermediate state instead of five
theoretically predicted ones. Here we address the open question regarding the spin-relaxation mechanism using our
embedding approach (CI-cRPA) based on configuration
interaction and a screened electron-electron interaction derived
from hybrid density functional theory. Our approach yields a fine
structure of the quartet states of VSi consistent with literature
and enables us to draw a quantitative picture of the spin-orbit
coupling in the spin-relaxation path. Besides VSi, we also
address the di-vancancy in SiC and the NV center in diamond.
Forschungs-