STRUCTURE AND DYNAMICS OF PEROVSKITE-TYPE CRYSTALS

被引：204
作者：
COCHRAN, W
ZIA, A
机构：
[1] Department of Natural Philosophy, University of Edinburgh
来源：
PHYSICA STATUS SOLIDI | 1968年 / 25卷 / 01期
关键词：
D O I：
10.1002/pssb.19680250126
中图分类号：
O469 [凝聚态物理学];
学科分类号：
070205 ;
摘要：
The connection between Landau's theory of phase transitions and the lattice‐dynamical theory of a displacive transition in a crystal is discussed. At a second‐order displacive transition the frequency of one normal mode becomes zero. By investigating the displacements of the atoms from special positions of the lattice for a number of crystals having the distorted perovskite structure, we have shown that several modes are involved in the various transitions, except in the case of LaAlO3, where the transition is probably second‐order or nearly so, and is associated with a mode of low frequency. The wave vector of this mode is at the point (1/2 1/2 1/2) of the Brillouin zone, and its irreducible representation is Γ25. Copyright © 1968 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
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页码：273 / &
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