高压下Gd_2Zr_2O_7结构变化第一性原理的研究  

Research in Structure Changes of Gd_2Zr_2O_7 Under High Pressure by the First-Principle Calculation

作　　者：鲁明亮[1] 王春[1] 

机构地区：[1]江苏省联合职业技术学院南京分院,江苏南京210019

出　　处：《科技创新导报》2015年第8期31-34,共4页Science and Technology Innovation Herald

摘　　要：Gd_2Zr_2O_7作为一种绝缘体材料广泛用于在飞机发动机及燃气轮机的热障涂层,该文利用第一性原理对Gd_2Zr_2O_7随着压强的增加产生的结构相变进行了研究,发现Gd_2Zr_2O_7在压强为28.5GP时,由焦绿石结构(pyrochlore)变为有缺陷的萤石结构(defect-fluorite);当压强加到43.2GP时,晶格结构被扭曲,变为扭曲的萤石结构(distorted defect-fluorite)。该文还对Gd_2Zr_2O_7电子结构进行了计算,通过分析态密度图发现,当压强到达15.3GP时,带隙宽度3eV减小到0.5eV,晶体由绝缘体转变为半导体,继续加压到28.5GP时,带隙宽度变为3.7eV,晶体又由半导体转变为绝缘体。The pyrochlore can be widely applied as Thermal Barrier Coatings（TBCs）in airplane engine and gas turbine. The pyrochlore Gd2Zr2O7 with different pressure has been studied by ab initio band calculation based on the density functional theory. With higher pressure on the pyrochlore Gd2Zr2O7,the crystal has a tendency to transform from the pyrochlore to the defect--fluorite structure at the pressure about 28.5GP and then becomes the distorted defect--fluorite at the pressure 3.2GP. We calculate the electron structure and by the analysis of the DOS pictures we discovered that the crystal transforms from semiconductor to insulator near the 15.3GP pressure. With the energy gap changing from 3ev to 0.5ev, the crystal changes from insulator to semiconductor. While the pressure arrives to 28.5GP and then the energy gap will increase from 0.5ev to 3.7ev, meanwhile the crystal changes from semiconductor to insulator.

关 键 词：Gd2Zr2O7结构 第一性原理 压强 结构相变 焦绿石结构 萤石结构 

分 类 号：O4[理学—物理]