ELFT HÍRADÓ

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PhD Preliminary DefenseGhafari Cherati, Nima HUN-REN Wigner RCP 
SZFIInvestigation of point defects in diamond by means of ab initio 
simulationsThursday, 18 June 2026, 14:00, KFKI Campus, Bldg. 1, 2nd floor, 
Conference RoomPoint defects in diamond are promising building blocks for 
quantum technologies because they can host localized electronic states with 
useful optical and spin properties. In my work, first-principles calculations 
based on density functional theory were used to investigate selected defect 
complexes in diamond and to connect their atomic structures with 
experimentally measurable properties, including formation energies, 
charge-state stability, electronic levels, zero-field splitting, hyperfine 
interactions, vibrational signatures, and optical transitions.Three classes 
of defects were studied. Oxygen–vacancy complexes were examined as possible 
microscopic models of the ST1 color center, but their calculated triplet 
ground states rule them out as candidates for ST1, while identifying 
oxygen-vacancy complexes as potentially interesting paramagnetic or optically 
active defects. Carbon self-interstitial aggregates were investigated as 
candidates for intrinsic optical centers such as TR12 and 3H, revealing 
systematic trends in their stability, bonding, vibrational properties, and 
optical activity. Sulfur-related defects were analyzed to clarify their role 
in enhancing NV-center creation, showing that vacancy charging and hydrogen 
trapping can suppress competing defect formation pathways. These results 
provide atomistic insight into the identification and engineering of diamond 
defects for quantum-technology applications. Minden érdeklődőt szívesen 
látunk! - Everyone is welcome to attend.Tamás 
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