Studies of the local distortions for nd¹ (Mo⁵⁺ and W⁵⁺) impurities in KTP crystals

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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 ; Xian-Fen Hu ; Guo-Liang Li
• 关键词：Defect structures ; Electron paramagnetic resonance (EPR) ; Mo5+ ; W5+ ; KTiOPO4 (KTP)
• 刊名：Polyhedron
• 出版年：2016
• 出版时间：17 February 2016
• 年：2016
• 卷：105
• 期：Complete
• 页码：71-76
• 全文大小：731 K

文摘

4d¹ (Mo⁵⁺) and 5d¹ (W⁵⁺) impurities doped into nonlinear optical crystals KTiOPO₄ (KTP) can occupy the inequivalent Ti1 and Ti2 sites and exhibit orthorhombically compressed octahedral nd¹ (n = 4, 5) centres arising from the Jahn–Teller effect. Closely relevant to the electronic levels as well as optical and magnetic properties of these materials, the above local distortions can be suitably reflected by the anisotropic electron paramagnetic resonance (EPR) signals with the paramagnetic nd¹ probes. This work stresses on the theoretical studies of the EPR parameters (g factors g_x, g_y, g_z and hyperfine structure constants A_x, A_y, A_z) and local distortions for the above nd¹ impurity centres in a consistent way. The local distortions are characterised by the relative axial compression ratios ρ (≈0.040, 0.032 and 0.031) and the relative planar bond length variation ratios τ (≈0.030, 0.015 and 0.012) for Mo⁵⁺ centre I and W⁵⁺ centres II and III, respectively, which are larger than those of host Ti1 and Ti2 sites.