HoVO_4相变的高压拉曼光谱和理论计算研究  

Study of phase transition of HoVO_4 under high pressure by Raman scattering and ab initio calculations

作　　者：陈元正[1,2] 李硕[2] 李亮[2] 门志伟[2] 李占龙[2] 孙成林[2] 里佐威[2] 周密[1,2] 

机构地区：[1]吉林大学超硬材料国家重点实验室,长春130012 [2]吉林大学物理学院,长春130012

出　　处：《物理学报》2013年第24期239-243,共5页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:11104107);高等学校博士学科点专项科研基金(批准号:20110061120008);中国博士后科学基金(批准号:20110491320;2012T50285);吉林省基础研究计划(批准号:20130522189JH)资助的课题~~

摘　　要：利用高温固相反应法制备了纯相的HoVO4,并在0—21.25 GPa压强范围内测定了HoVO4的拉曼光谱.通过分析其拉曼峰的频移和劈裂变化情况,发现HoVO4在9.3 GPa发生相变.根据第一性原理选取并优化相似体系的高压晶体结构,将其与HoVO4的常压锆石矿型I41/amd结构进行了能量比较,确认HoVO4相变结构为白钨矿型结构(I41/a).研究结果表明,HoVO4具有ScVO4和YVO4体系的从锆石矿型结构(I41/amd)至白钨矿型结构的相变过程.分析对应结构相的体积随压强的变化,发现体积坍塌对该相变起重要作用.上述研究结果有助于了解HoVO4的高压结构以及该材料在高压特殊条件下的应用.The aim of this work is to confirm that the HoVO4 has a zircon-to-scheelite phase transition as reported in ScVO4 and YVO4. Firstly, we prepare HoVO4 samples used in the experiments by solid state reaction of appropriate quantities of pre-dried Ho2 O3 and V2 O5. And the Raman spectra of HoVO4 are measured in a pressure range from ambient pressure to 21.25 GPa at room temperature by using a diamond anvil cell. The discontinuities on Raman mode shifts and the occurrence of new Raman bands provide strong evidence for a phase transition at 9.3 GPa. Secondly, ab initio calculations are performed and the results reveal a zircon-type（I41/amd） to scheelite-type（I41/a） structure in this phase transition. The results are compared with those previously reported for the relevant ScVO4 and YVO4 with a common zircon-to-scheelite phase transition, mainly duo to volume collapses. The results in this work may improve our understanding of the high phase and structure of HoVO4 and benefit the application of this material.

关 键 词：锆石矿型结构 白钨矿型结构 拉曼光谱 第一性原理 

分 类 号：O433[机械工程—光学工程]