Investigations of the spin Hamiltonian parameters for the cubic Mn2+ centers in ZnX (X = S, Se, Te) and CdTe

2010 ◽  
Vol 88 (5) ◽  
pp. 301-306 ◽  
Author(s):  
Xue-Feng Wang ◽  
Shao-Yi Wu ◽  
Li-Li Li ◽  
Shan-Xiang Zhang
Keyword(s):  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Pure Spin ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Good Agreement ◽  
G Factors

The spin Hamiltonian parameters (g factors and the hyperfine structure constants) for the cubic Mn2+ centers in ZnX (X = S, Se, Te) and CdTe are investigated theoretically using the perturbation formulas of these parameters for a tetrahedral 3d5 cluster containing both the crystal-field and charge-transfer contributions. The relevant molecular orbital coefficients are uniformly determined from the cluster approach, and the calculated spin Hamiltonian parameters are in good agreement with the observed values. The g-shifts of the g factors related to the pure spin value gs (≈ 2.0023) arising from the charge transfer contributions are opposite (positive) in sign and much larger in magnitude than those from the crystal field contributions. On the other hand, the contributions from the charge-transfer mechanism to the hyperfine structure constants are the same in sign and about 20%–30% in magnitude of those from the crystal-field mechanism. The importance of the charge transfer contributions increases significantly with the increase of the covalency and the spin–orbit coupling coefficient of the ligand, i.e., S2− < Se2− < Te2−.

INVESTIGATIONS OF THE EPR PARAMETERS FORDy3+CENTER INZrSiO4CRYSTAL

2010 ◽  
Vol 24 (03) ◽  
pp. 289-296 ◽  
Author(s):  
HUI-NING DONG ◽  
DENG-FENG LI ◽  
JUN LIU ◽  
DAVID J. KEEBLE
Keyword(s):  
Crystal Field ◽  
Tetragonal Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Field Interaction ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The electronic paramagnetic resonance g factors g‖, g⊥of Dy3+centers and the hyperfine structure constants A‖and A⊥of161Dy3+and163Dy3+isotopes in ZrSiO4crystal are theoretically studied from the perturbation formulas of the spin Hamiltonian parameters for a 4f9ion in tetragonal symmetry. In these formulas, the contributions to g factors due to the J-mixing among the ground6H15/2, the first excited6H13/2and second excited6H11/2states via crystal-field interaction, the admixtures among the states with the same J value via spin-orbit coupling interaction and the interactions between the lowest Kramers doublet Γγ and other 20 Kramers doublets ΓXwithin the states6HJ(J=15/2, 13/2 and 11/2) via crystal-field and orbital angular momentum interactions are considered. The calculated EPR parameters show reasonable agreement with the observed values. The results are discussed.

Studies of the g Factors and the Hyperfine Structure Constants for the Octahedral Interstitial Mn2+ and Cr+ Impurities in Silicon

2013 ◽  
Vol 68 (5) ◽  
pp. 337-342 ◽  
Author(s):  
Bo-Tao Song ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Li-Li Li
Keyword(s):  
Experimental Data ◽  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Structure Constant ◽  
Cluster Approach ◽  
Hyperfine Structure Constant ◽  
Structure Constants ◽  
Good Agreement ◽  
G Factors

The g factors and the hyperfine structure constants for the octahedral interstitial Mn2+ and Cr+ impurities in silicon are theoretically studied using the perturbation formulas of these parameters for an octahedral 3d5 cluster. In the calculations, both the crystal-field and charge transfer contributions are taken into account in a uniform way, and the related molecular orbital coefficients are quantitatively determined from the cluster approach. The theoretical g factors and the hyperfine structure constants are in good agreement with the experimental data. The charge transfer contribution to the g-shift (≈g-gs, where gs ≈ 2:0023 is the spin only value) is opposite (positive) in sign and about 51% - 116% in magnitude as compared with the crystal-field one for Mn2+ and Cr+, respectively. Nevertheless, the charge transfer contribution to the hyperfine structure constant has the same sign and about 12% - 19% that of the crystal-field one. Importance of the charge transfer contribution shows the order Cr+ < Mn2+ due to increase of the impurity valence state in the same host, especially for the g factor.

Investigation of the Spin Hamiltonian Parameters of Yb3+ in CaWO4 Crystal

2004 ◽  
Vol 59 (12) ◽  
pp. 943-946 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Second Order ◽  
Order Perturbation ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

In this paper, the spin Hamiltonian parameters g factors g∥ and g⊥ of Yb3+ and hyperfine structure constants A∥ and A⊥ of 171Yb3+ and 173Yb3+ in CaWO4 crystal are calculated from the two-order perturbation formulae. In these formulae, the contributions of the covalence effects, the admixture between J =7/2 and J =5/2 states as well as the second-order perturbation are included. The needed crystal parameters are obtained from the superposition model and the local structure of the studied system. The calculated results are in reasonable agreement with the observed values. The results are discussed.

INVESTIGATIONS ON THE SPIN HAMILTONIAN PARAMETERS FOR Nd3+ IN ThGeO4

2007 ◽  
Vol 21 (02) ◽  
pp. 191-197
Author(s):  
SHAO-YI WU ◽  
HUI-NING DONG
Keyword(s):  
Hyperfine Structure ◽  
Second Order ◽  
Experimental Results ◽  
Order Perturbation ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The spin Hamiltonian parameters, g factors g‖ and g⊥, for Nd 3+ in ThGeO 4 are theoretically investigated from the perturbation formulas of the g factors for a 4f3 ion in tetragonal symmetry. In these formulas, the contributions to the g factors from the second-order perturbation terms and the admixture of various states are taken into account. It is found that the calculated g factors of this work are smaller than the experimental results, but close to those in the previous theoretical studies by Gutowska et al. Moreover, the calculated hyperfine structure constants A‖ and A⊥ as well as the energies of the 4I9/2 Stark levels in this work are also consistent with those in the previous investigations. The discrepancy between theoretical and experimental g factors is discussed.

Studies of the Spin Hamiltonian Parameters for Cubic V2+, Cr3+, and Mn4+ Centers In MgO and CaO, Based on Two Mechanism Models

2004 ◽  
Vol 59 (10) ◽  
pp. 689-693 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Structure Constant ◽  
Order Perturbation ◽  
Spin Hamiltonian ◽  
Mechanism Model ◽  
Hyperfine Structure Constant ◽  
Hamiltonian Parameters ◽  
Theoretical Results

The high-order perturbation formulas of the spin Hamiltonian (SH) parameters g-shift Δg (=g−gs) and the hyperfine structure constant A for a 3d3 ion in cubic octahedra are established, based on the two mechanism model. In this model, not only the contributions from the conventional crystal-field (CF) mechanism, but also those from the charge-transfer (CT) mechanism are taken into account. These formulas are applied to the investigation of the SH parameters of cubic V2+, Cr3+ and Mn4+ centers in MgO and CaO. Based on these studies, the sign of Δg due to the CT mechanism is opposite to that due to the CF mechanism, while the signs of the A factor due to the CF and CT mechanisms are equal. The theoretical results, including the contributions from the CF and CT mechanisms, agree better with the observed values than those containing only the conventional CF mechanism.

Theoretical Investigations of the Spin Hamiltonian Parameters and the Local Structure of a Trigonal Co2+ Center in Bi4Ge3O12

2004 ◽  
Vol 59 (9) ◽  
pp. 563-567
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dongb
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Trigonal Symmetry ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The spin Hamiltonian parameters anisotropic g factors g||, g⊥ and hyperfine structure constants A||and A⊥, as well as the local structure of the trigonal Co2+ center in Bi4Ge3O12 (BGO) are theoreticallyinvestigated by the perturbation formulas of the spin Hamiltonian parameters for a 3d7 ion intrigonal symmetry, based on the cluster approach. It is found that the impurity Co2+ substituting thehost Bi3+ undergoes an off-center displacement ΔZ(≈ −0.132 Å ) away from the center of the oxygenoctahedron along the C3 axis. The spin Hamiltonian parameters based on the above displacementshow reasonable agreement with the observed values. The results are discussed.

STUDIES ON THE LOCAL STRUCTURE AND THE SPIN HAMILTONIAN PARAMETERS FOR THE TRIGONAL Mn2+ CENTER IN Bi4Ge3O12

2008 ◽  
Vol 22 (14) ◽  
pp. 1381-1387 ◽  
Author(s):  
XUE-FENG WANG ◽  
SHAO-YI WU ◽  
ZHI-HONG ZHANG ◽  
LI-HUA WEI ◽  
YUE-XIA HUA
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Trigonal Symmetry ◽  
Oxygen Octahedron ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Good Agreement

The local structure and the spin Hamiltonian parameters (the zero-field splitting D, the g factors g//, g⊥ and the hyperfine structure constants A// and A⊥) for the trigonal Mn 2+ center in Bi 4 Ge 3 O 12 are theoretically studied from the perturbation formulas of these parameters for a 3d5 ion in trigonal symmetry. The impurity Mn 2+ replacing host Bi 3+ is not found to occupy the exact Bi 3+ site but to suffer a large off-center displacement by about 0.36 Å towards the center of the oxygen octahedron along the C3-axis due to the size and charge mismatching substitution. The calculated spin Hamiltonian parameters based on the above displacement show good agreement with the observed values. The results and the mechanism of the impurity displacement are discussed.

Theoretical Studies of the Spin Hamiltonian Parameters for Fe0 and Mn– in Silicon Center

2013 ◽  
Vol 634-638 ◽  
pp. 2518-2522
Author(s):  
Min Quan Kuang ◽  
Shao Yi Wu ◽  
Bo Tao Song ◽  
Xian Fen Hu
Keyword(s):  
Experimental Data ◽  
Hyperfine Structure ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Valence States ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Theoretical Results ◽  
Good Agreement

The spin Hamiltonian parameters (g factors and the hyperfine structure constants) for the octahedral interstitial Fe0and Mn in silicon are theoretically investigated using the perturbation formulas of these parameters for a 3d8ion under octahedral environments based on the cluster approach. The theoretical results show good agreement with the experimental data, and the ligand contributions should be considered due to the strong covalency of the systems. The interstitial occupation of the above novel 3d8impurities of rare valence states in silicon is discussed.

Theoretical Studies of the Local Structures and Spin Hamiltonian Parameters for the Cu2+ Centers in Alkali Barium Borate Glasses

2013 ◽  
Vol 344 ◽  
pp. 89-93
Author(s):  
Wang He Wei ◽  
Min Lu ◽  
Chun Ju Hou
Keyword(s):  
Hyperfine Structure ◽  
Relative Elongation ◽  
Borate Glasses ◽  
Barium Borate ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Local Structures ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Good Agreement

The spin Hamiltonian parameters (g factors g||, g and the hyperfine structure constants A||, A) for the Cu2+centers in alkali barium borate glasses were theoretically studied based on the high-order perturbation formulas of these parameters for a 3d9ion in a tetragonally elongated octahedron. From the calculations, the ligand octahedra around Cu2+are suggested to suffer about 9.4%, 10.7%, and 11.1% relative elongation along C4 axis for the alkali barium borate glasses (Li-Ba-B, Na-Ba-B and K-Ba-B, respectively), the results are in good agreement with the observed values. In addition, the negative signs for A|| and A of the studied Cu2+centers were also suggested in the discussion.

Investigations on the spin Hamiltonian parameters of Cu(2) site in (Tl0.5Pb0.5)Sr2CaCu2O7 superconductors

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542018
Author(s):  
Xian-Fen Hu ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Min-Quan Kuang
Keyword(s):  
Hyperfine Structure ◽  
Ground State ◽  
Reduction Factor ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Hamiltonian ◽  
Core Polarization ◽  
Ligand Orbital ◽  
Structure Constants ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters ([Formula: see text] factors and hyperfine structure constants) of the five-fold coordinated Cu(2) site in [Formula: see text] superconductors are investigated from the high order perturbation formulas of these parameters for a [Formula: see text] ion in tetragonally elongated octahedron. The observed anisotropies [Formula: see text] and [Formula: see text] are ascribed to the [Formula: see text] ground state for [Formula: see text] under octahedral tetragonal elongation distortion. The comparable magnitudes of the parallel and perpendicular hyperfine structure constants may be illustrated by the small core polarization constant and the reduction factor [Formula: see text]. The ligand orbital and spin–orbit coupling contributions are found to be important due to significant covalency and should be considered in the calculations.

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