ELFT HÍRADÓ

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

SZFI SeminarRohit Babar Linköping University (host: Barcza Gergely)Spin 
centers in boron nitride and silicon carbide for quantum technology 
applicationsTuesday, 10 May 2022, 10:00, Bldg 1, auditorium, 
https://wigner-hu.zoom.us/j/85242181421?pwd=MjFxTGNIR1ZFSHlXTlRaeWRhZVIrUT09  
 Meeting ID: 852 4218 1421  Passcode: 648715Spin centers in wide-bandgap 
semiconductors have emerged as promising candidates for quantum 
communication, storage, and sensing applications. The spin centers typically 
comprise optically active intrinsic defects or dopant atoms in semiconducting 
host, with the feasibility of spin coherent, bright emission, and stable 
operation determined by the spin center-host interactions. The emergence of 
spin centers in two-dimensional host represents a new milestone in nanoscale 
sensing as the increased proximity to source could lead to high-resolution 
sensors. In this talk, I will present the first-principles study of novel 
spin centers in hexagonal boron nitride (hBN). We investigate the stability 
and magneto-optical properties of boron vacancy pair in the neutral charge 
state. This spin center is optically addressable with a long-lived memory, 
and can serve as a sensor with an efficient coherence protection scheme 
within a dense nuclear spin environment. Similarly, the tetramer carbon 
clusters in hBN are identified as potential spin centers with zero phonon 
line emission in the visible spectral range. Among bulk semiconductors, the 
mature growth and implantation techniques for silicon carbide (SiC) have led 
to controlled generation of spin centers. The negatively charged silicon 
vacancy in 4H-SiC is a widely reported spin center, however, the source of 
electron paramagnetic resonance and photoluminescence measurements close to 
the vacancy remains unknown. Based on our combined theory and experiment 
investigation, we attribute these signals to silicon vacancy perturbed by 
neighboring carbon antisite. Lastly, we demonstrate the modification of spin 
center properties in the presence of an extended defect. For the 
divacancy-stacking fault complex in 4H-SiC, the distinct divacancy 
configurations within the stacking fault show a large zero-field splitting. 
This could potentially lead to development of robust spin centers by further 
improving the coherence protection scheme achieved for basal divacancies in 
4H-SiC.  Minden érdeklődőt szívesen látunk! - Everyone is welcome to 
attend.Róbert Juhászsem-admin AT szfki.hu