Theoretical investigations on the defect structures and spin Hamiltonian parameters for various orthorhombic Rh²⁺ centres in KTiOPO₄ and KTiOAsO₄

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• 作者：Chang-Chun Ding ; ^{ccding626@163.com" class="auth_mail" title="E-mail the corresponding author} ; Shao-Yi Wu ; ^{wushaoyi@uestc.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Li-Juan Zhang ; Guo-Liang Li ; Zhi-Hong Zhang
• 关键词：Defect structures ; Electron paramagnetic resonance (EPR) ; Spin Hamiltonians ; Rh2+ ; KTiOAsO4 (KTA) and KTiOPO4 (KTP)
• 刊名：Physica B: Physics of Condensed Matter
• 出版年：2015
• 出版时间：15 December 2015
• 年：2015
• 卷：479
• 期：Complete
• 页码：21-25
• 全文大小：440 K

文摘

The defect structures and spin Hamiltonian parameters (SHPs) for three Rh²⁺ centres (denoted C₁ in KTiOAsO₄ and C₂ and C₃ in KTiOPO₄) are theoretically investigated by utilising the perturbation formulae for a 4d⁷ ion under orthorhombically (D_2h) elongated octahedra. The defect structures are characterized by the axial elongation ratios of 4.91%, 4.93% and 4.90% along the Z axis and the planar bond length variation ratios of 0.05%, 0.01% and 0.04% for centres C₁, C₂ and C₃, respectively, owing to the Jahn–Teller effect. The nearly identical moderate axial elongation ratios and the slightly different tiny planar bond length variation ratios may suitably account for the comparable moderate axial g anisotropies 鈭?em>g (≈0.6087, 0.6124 and 0.6067) and the slightly dissimilar tiny perpendicular g anisotropies 未g (≈0.0649, 0.0097 and 0.0509) of the three centres, respectively. All centres demonstrate similar strong crystal-field interactions and moderate covalence arising from the comparable short impurity-ligand distances.