无机材料学报 ›› 2011, Vol. 26 ›› Issue (5): 491-494.DOI: 10.3724/SP.J.1077.2011.00491 CSTR: 32189.14.SP.J.1077.2011.00491

• 研究论文 • 上一篇    下一篇

分子动力学方法模拟压强对Bi4Ti3O12铁电相变行为的影响

孙玲玲1, 马 颖1,2, 周益春1,2   

  1. (湘潭大学 1. 材料与光电物理学院; 2. 低维材料及其应用技术教育部重点实验室, 湘潭 411105)
  • 收稿日期:2010-07-14 修回日期:2010-09-09 出版日期:2011-05-20 网络出版日期:2011-06-07
  • 作者简介:孙玲玲(1985-), 女, 硕士研究生. E-mail: kuailesunling@163.com
  • 基金资助:

    国家自然科学基金(10702059); 教育部博士点新教师基金(20070530009); 教育部留学回国人员科研启动基金(2008890); 国家博士后科学基金(20090451102)

Study on Pressure-induced Ferroelectric Phase Transition in Bi4Ti3O12 by Molecular Dynamics Simulation

SUN Ling-Ling1, MA Ying1,2, ZHOU Yi-Chun1,2   

  1. (1. Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan 411105, China; 2. Key Laboratory of Low Dimensional Materials & Application Technology, Ministry of Education, Xiangtan 411105, China)
  • Received:2010-07-14 Revised:2010-09-09 Published:2011-05-20 Online:2011-06-07
  • Supported by:

    National Natural Science Foundation of China (10702059); Doctoral Program of Higher Education of Ministry of Education of China (20070530009); Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education (2008890); China Postdoctoral Science Foundation (20090451102)

摘要: 在壳模型的基础上, 通过分子动力学方法模拟了压强对Bi4Ti3O12(BIT)铁电相变行为的影响. 为了提高模拟的准确性, 在原有势参数的基础上增加了Ti-Ti短程相互作用势. 计算得出了温度为300K时BIT单晶的铁电正交B2cb相在x方向和z方向的自发极化强度分别为39.4μC/cm2和0, 与实验结果较好的吻合. 然后模拟了压强对BIT相变行为的影响. 模拟结果表明: BIT单晶在压强从-2 GPa到24 GPa范围内, 经历了两次结构相变, 分别发生在  6 GPa和20 GPa处. 这种对称性的改变类似于在环境压力条件下温度导致BIT单晶对称性的改变. 因而模拟结果为研究压强引起BIT的相变行为提供了理论依据.

关键词: 分子动力学, Bi4Ti3O12, 压强, 相变

Abstract: Pressure-induced phase transition of Bi4Ti3O12 (BIT) was studied using a shell model via molecular dynamics method. The Ti?Ti short range interaction potential was added to increase the accuracy of the simulation. The calculated spontaneous polarizations of ferroelectric orthorhombic B2cb phase BIT single crystal were 39.4μC/cm2 in the x direction and 0 in the z direction at 300K, which were in reasonable agreement with the experimental values. The pressure-induced phase transition of BIT was also calculated. It was observed that BIT single crystal underwent two structural transformations at around 6GPa and 20GPa with increasing pressure from -2GPa to 24GPa. The accompanying symmetry changes may be the same as those observed at ambient pressure at elevated temperature. Thus the results provide a theoretical prediction of the pressure-induced phase transition in BIT.

Key words: molecular dynamics, Bi4Ti3O12, pressure, phase transition

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