钼酸镧氧离子导体结构与扩散性质的分子动力学研究  

Molecular Dynamics Study of Crystal Structure and Diffusion of Oxide Ionic Conductors Lanthanum Molybdate

作　　者：侯春菊[1] 张旭[2] 刘长松[3] 方前锋[3] 

机构地区：[1]江西理工大学理学院,赣州341000 [2]江西理工大学材料与化学工程学院,赣州341000 [3]中国科学院固体物理研究所,合肥230031

出　　处：《材料导报》2010年第6期71-74,77,共5页Materials Reports

基　　金：国家自然科学基金(10674135;50672100)

摘　　要：基于密度泛函的方法研究了β-La2Mo2O9的结构性质与扩散行为。研究首次发现结构中Mo有MoO4和MoO52种形式的多面体,并且O(1)、O(2)和O(3)3种氧位置的占有率分别为100%、91.7%和25%,与实验相符。所有结构可通过P213的12个对称操作而互相转换,得到的结构可能是局部或本征极小结构。扩散研究结果显示,氧离子(空位)扩散是一种多离子间协同的集体运动行为,3个扩散通道可能与高温相的高电导有关,其中激活能为1.05eV和1.24eV的2个扩散通道可能与内耗弛豫峰有关。The structure and diffusion of β-La2 Mo2O9 are studied with the framework of the density-functional theory. It is found that the occupancies of three crystallographic distinct O sites O（1）,O（2） and O（3） are 100%, 91.7 % and 25 %, respectively, consistent with experiments. Each Mo cation is surrounded by four or five O-ions. All configurations are related to each other by one of 12 symmetry operations of P21 3 space group, the structure observed experimentally may he interpreted as a time and spatial average of these local or inherent structures. The O ions move in a cooperative fashion. Three diffusion channels are found to be responsible for the high conductivity, and two channels with activation energies of 1.05eV and 1.24eV to be responsible for mechanical relaxation peaks.

关 键 词：氧离子导体 La2Mo2O9 分子动力学氧空位扩散 

分 类 号：O552.32[理学—热学与物质分子运动论]