Theoretical prediction of ion conductivity in solid state HfO_2

作     者：张炜 陈文周 孙久雨 姜振益 

作者机构：School of Science Xi'an University of Posts and Telecommunications Institute of Modern Physics Northwest University 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2013年第22卷第1期

页      面：441-446页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 10647008 and 50971099) the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20096101110017) 

主　　题：ion conduction diffusion in solids ionic crystals density functional calculations 

摘      要：A theoretical prediction of ion conductivity for solid state HfO2 is carried out in analogy to ZrO2 based on the density functional calculation. Geometric and electronic structures of pure bulks exhibit similarity for the two materials. Negative formation enthalpy and negative vacancy formation energy are found for YSH （yttria-stabilized hafnia） and YSZ （yttria- stabilized zirconia）, suggesting the stability of both materials. Low activation energies （below 0.7 eV） of diffusion are found in both materials, and YSH＇s is a little higher than that of YSZ. In addition, for both HfO2 and ZrO2, the supercells with native oxygen vacancies are also studied. The so-called defect states are observed in the supercells with neutral and ＋1 charge native vacancy but not in the ＋2 charge one. It can give an explanation to the relatively lower activation energies of yttria-doped oxides and ＋2 charge vacancy supercells. A brief discussion is presented to explain the different YSH ion conductivities in the experiment and obtained by us, and we attribute this to the different ion vibrations at different temperatures.