Fine Structure of Triplet Centers in Room Temperature Irradiated 6H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 403-406 ◽  
Author(s):  
Andreas Scholle ◽  
Siegmund Greulich-Weber ◽  
Eva Rauls ◽  
Wolf Gero Schmidt ◽  
Uwe Gerstmann

In non-annealed 6H-SiC samples that were electron irradiated at room temperature, a new EPR signal due to a S=1 defect center with exceptionally large zero-field splitting (D = +652•10-4 cm-1) has been observed under illumination. A positive sign of D demonstrates that the spin-orbit contribution to the zero-field splitting exceeds by far that of the spin-spin interaction. A principal axis of the fine structure tilted by 59° against the crystal c-axis as well as the exceptionally high zero-field splitting D can be qualitatively understood by the occurrence of additional close-lying defect levels in defect clusters resulting in comparatively large second-order spin-orbit coup¬ling. A tentative assignment to vacancy clusters is supported by the observed annealing behavior.

2006 ◽  
Vol 61 (5-6) ◽  
pp. 289-292 ◽  
Author(s):  
Hong-Gang Liu ◽  
Xiao-Xuan Wu ◽  
Wen-Chen Zheng ◽  
Lv He

The EPR zero-field splitting D (= b02 ) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2 :Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed


1972 ◽  
Vol 27 (7) ◽  
pp. 1082-1093
Author(s):  
R Krieger ◽  
J Voitländer

AbstractThe zero-field splitting and g-values of manganocene and chromocene have been calculated. The wave functions were obtained by means of a self-consistent charge extended Huckel method. The calculated values g||=2.0034 and g⊥ = 2.0033 of manganocene agree fairly well with the experi­mental results obtained from ESR measurements. The very large computed zero-field splitting D= -0.24 cm-1 explains that there has been observed only one ESR transition though mangano­cene is in a spin-5/2 state. For chromocene no ESR transition has been found until now. We therefore studied the splitting of the orbitally degenerate ground state by the combined action of spin-orbit coupling and low-symmetry perturbation. The predicted splitting is strongly dependent on the magnitude of the rhombic distortion compared to the spin-orbit interaction. The g-values are highly anisotropic, with g|| =2.49 and g⊥ =1.97


2014 ◽  
Vol 16 (19) ◽  
pp. 9171-9181 ◽  
Author(s):  
Kenji Sugisaki ◽  
Kazuo Toyota ◽  
Kazunobu Sato ◽  
Daisuke Shiomi ◽  
Masahiro Kitagawa ◽  
...  

The CASSCF and hybrid CASSCF–MRMP2 methods reproduce the ZFS tensors of spin-septet 2,4,6-trinitrenopyridines, focusing on the heavy atom effects on the spin–orbit terms of the tensors.


2011 ◽  
Vol 13 (15) ◽  
pp. 6970 ◽  
Author(s):  
Kenji Sugisaki ◽  
Kazuo Toyota ◽  
Kazunobu Sato ◽  
Daisuke Shiomi ◽  
Masahiro Kitagawa ◽  
...  

2012 ◽  
Vol 15 (2-3) ◽  
pp. 250-254 ◽  
Author(s):  
Florian Senn ◽  
Lothar Helm ◽  
Alain Borel ◽  
Claude A. Daul

2013 ◽  
Vol 740-742 ◽  
pp. 389-392 ◽  
Author(s):  
Ekaterina N. Kalabukhova ◽  
Dariya Savchenko ◽  
Bela Shanina ◽  
Nikolai T. Bagraev ◽  
Leonid Klyachkin ◽  
...  

Triplet center with spin state S = 1 is detected in the EPR spectrum of the self-assembled 6H SiC nanostructure obtained by non-equilibrium boron diffusion into the n-type 6H SiC epitaxial layer (EL) under conditions of the controlled injection of the silicon vacancies at the temperature of T = 900°C. From the analysis of the angular dependences of the EPR spectrum and the numerical diagonalization of the spin Hamiltonian, the value of the zero-field splitting constant D and g-factor are found to be D = 1140•10-4см-1 and gpar = 1.9700, gper = 1.9964. Based on the hyperfine (hf) structure of the defect originating from the hf interaction with one 14N nuclei, the large value of the zero-field splitting constant D and technological conditions of the boron diffusion into the n-type 6H SiC EL, the triplet center is tentatively assigned to the defect center consisting of nitrogen atom and silicon vacancy.


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