结构相变中晶体学群论问题的讨论

Discussions of crystallographic space group problems in structural phase transitions

结构变化是相变的基本特征,而晶体学与群论是描述结构的语言。本文从晶体学群论入手,在概述了固体位移型相变的母群-子群关系的基础上,着重介绍了电子束诱导的扩散性相变^([1-2])中倒置的母群-子群关系,并从实验结果的分析得到一选择定则,对研究材料的辐照效应有着指导性作用。最后又讨论了在表面重构的过程中应用平面群的母群-子群关系分析的群论方法与实例。

Structural change is the basic of phase transformation,which can be described in terms of crystallographic group theory.The formation rules of two complementary structural transitions,the displacive and the desorption induced by electron transitions(DIET)[1-2]undergoing group-subgroup and inversed processing respectively,are presented with experimental examples.The significance of amorphous presented in DIET transition is shown in TiO2-nanowire formation,that leads a‘surface-vapor-liquid-solid’mechanism.Furthermore,an attempt of applying plane groups for the possible group-subgroup relationship of surface reconstructed structures is also discussed,which well interprets the formation of the strip domains grown on AlN surface.