Jahn-Teller Phase Transitions in RbCuCl_3

概要

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The phase transition at 66'C in RbCuC1. has been investigated by X-raydiffraction methods. Structure analyses have been carried out using the pho-tographic data. For high-temperature structure, three equally plausible spacegroups P6./mmc, P62c and P6.mc have been examined by a block diagonal leastsquares refinement. The room-temperature structure has the superstructure withthe lattice parameter doubled along the Z>-axis and the space group is Pbcn. Themode analysis of the Jahn-Teller active mode was carried out and the intensity dis-tribution of the superlattice reflections was consistent with the atomic shiftscorresponding to the zone boundary .Mj-mode. There exists the second-orderpiezodistortive coupling between the antiferrodistortive static displacements andthe homogeneous strains. From this coupling, the precise temperature dependenceof the superlattice reflection is derived.
社団法人日本物理学会の論文
1983-05-15