title: Investigations on the local angular distortions and the spin-Hamiltonian parameters for Ni+ in sulfides.
abstract: The local angular distortions and the spin-Hamiltonian parameters (the g factors and the hyperfine parameters) for Ni(+) in ABS(2) (A=Cu, Ag; B=Al, Ga) ternary sulfides are theoretically investigated from the perturbation formulas of these parameters for 3d(9) ions in a tetragonally distorted tetrahedron. In view of the strong covalency of such systems, the ligand orbital and spin-orbit coupling contributions are taken into account using the cluster approach. The local impurity-ligand bond angles in the Ni(+) centers are found to be about 1.4-4.5 degrees smaller than those of the host monovalent A sites in the pure crystals, due to size mismatching substitution. As a result, the ligand tetrahedra exhibit slight elongation in CuBS(2):Ni(+) and slight compression in AgGaS(2):Ni(+). The calculated spin-Hamiltonian parameters, optical transitions and the relative intensity ratios show reasonable agreement with the experimental data.
authors.affiliation: Department of Applied Physics, University of Electronic Science & Technology of China, Chengdu 610054, PR China.
authors.forename: Hua-Ming
authors.initials: HM
authors.lastname: Zhang
authors.forename: Shao-Yi
authors.initials: SY
authors.lastname: Wu
authors.forename: Yue-Xia
authors.initials: YX
authors.lastname: Hu
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Wang
authors.forename: Pei
authors.initials: P
authors.lastname: Xu
mesh_terms: D002412:Cations / Q000737:chemistry*; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy; D008956:Models, Chemical; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D002412:Cations; D013440:Sulfides; D009532:Nickel