...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta Crystallographica, Section B. Structural Science >Symmetry rules and strain/order-parameter tionships for coupling between octahedral tilting and cooperative Jahn–Teller transitions in АВХ_З perovskites. I. Theory
【24h】

Symmetry rules and strain/order-parameter tionships for coupling between octahedral tilting and cooperative Jahn–Teller transitions in АВХ_З perovskites. I. Theory

机译：八面体倾斜与АВХ_З钙钛矿中协同Jahn-Teller跃迁之间耦合的对称性规则和应变/阶数参数。一，理论

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Space groups, order-parameter and strain/order-parameter coupling relationships in АВХ_З perovskite structures which combine cooperative Jahn—Teller distortions and octahedral tilting have been investigated from the perspective of group theory using the computer program ISOTROPY.Two common Jahn—Teller ordering schemes are associated with the irreducible representations М and R3 of the space group Pram. A third, less-common ordering scheme is associated with Г. These combine with tilting instabilities associated with M3 and R_4~+ to generate a predicted suite of Jahn—Teller structure types that includes many of the known structures of manganites, vanadates, Cu and Cr halides. Order-parameter coupling and passible phase transitions are described using Landau free-energy expansions, and general expressions for the relationships between symmetry-adapted spontaneous strains and particular order-parameter components are presented. These provide a general formal framework for determining structural evolution across multi-component order-parameter space and for characterizing the influence of tilting instabilities on Jahn—Teller instabilities or of Jahn—Teller ordering on octahedral tilting.
机译：使用计算机程序ISOTROPY，从群论的角度研究了结合协作Jahn-Teller变形和八面体倾斜的АВХ_З钙钛矿结构中的空间群，阶参数和应变/阶-参数耦合关系。两种常见的Jahn-Teller排序方案与空间群Pram的不可约表示М和R3相关联。第三种不太常见的排序方案与Г相关。这些结合了与M3和R_4〜+相关的倾斜不稳定性，从而生成了一套预测的Jahn-Teller结构类型，其中包括许多已知的锰矿，钒酸盐，Cu和Cr卤化物结构。使用Landau自由能展开描述了阶跃参数耦合和可通过相变，并给出了对称自适应自发应变与特定阶跃参数分量之间关系的一般表达式。这些提供了一个通用的正式框架，可以用来确定跨多阶有序参数空间的结构演化，以及表征倾斜不稳定性对Jahn-Teller不稳定性或Jahn-Teller有序对八面体倾斜的影响。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号