Spin-polarized electron paramagnetic resonance spectra of radical pairs in micelles: observation of electron spin-spin interactions

1987 ◽  
Vol 91 (13) ◽  
pp. 3592-3599 ◽  
Author(s):  
Gerhard L. Closs ◽  
Malcolm D. E. Forbes ◽  
James R. Norris
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Electron Spin ◽  
Radical Pairs ◽  
Paramagnetic Resonance ◽  
Spin Interactions ◽  
Spin Polarized ◽  
Electron Paramagnetic

Identification of Niobium in 4H-SiC by EPR and Ab Initio Studies

2012 ◽  
Vol 717-720 ◽  
pp. 217-220 ◽  
Author(s):  
Nguyen Tien Son ◽  
Viktor Ivády ◽  
Adam Gali ◽  
Andreas Gällström ◽  
Stefano Leone ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
High Temperature ◽  
Ab Initio ◽  
Electron Spin ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Paramagnetic Resonance ◽  
Form Complex ◽  
Electron Paramagnetic ◽  
Neutral Charge State

In unintentionally Nb-doped 4H-SiC grown by high-temperature chemical vapor deposition (HTCVD), an electron paramagnetic resonance (EPR) center with C1h symmetry and an electron spin S=1/2 was observed. The spectrum shows a hyperfine structure consisting of ten equal-intensity hyperfine (hf) lines which is identified as due to the hf interaction between the electron spin and the nuclear spin of 93Nb. An additional hf structure due to the interaction with two equivalent Si neighbors was also observed. Ab initio supercell calculations of Nb in 4H-SiC suggest that Nb may form complex with a C-vacancy (VC) resulting in an asymmetric split-vacancy (ASV) defect, NbSi-VC. Combining results from EPR and supercell calculations, we assign the observed Nb-related EPR center to the hexagonal-hexagonal configuration of the AVS defect in the neutral charge state, (NbSi-VC)0.

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