Diffuse scattering and lattice dynamics of superionic copper chalcogenides

被引:11
作者
Danilkin, Sergey A. [1 ]
机构
[1] Australian Nucl Sci & Technol Org, Bragg Inst, Lucas Heights, NSW, Australia
关键词
Ionic conduction; Crystal structure; Neutron scattering; Diffraction; HIGH-TEMPERATURE PHASES; X-RAY; CATION DISTRIBUTION; ROOM-TEMPERATURE; CU2SE; DIFFRACTION; SELENIDE; CU1.8SE;
D O I
10.1016/j.ssi.2008.06.012
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The energy-resolved neutron diffraction and inelastic neutron scattering study of diffuse scattering in copper chalcogenides was performed in order to clarify the role of static disorder versus low-energy phonons. Neutron diffraction patterns taken from Cu(1.75)Se, Cu(1.98)Se and Ag(0.25)Cu(1.75)Se powders in superionic phase show a broad maximum related to diffuse scattering. This diffuse background is suppressed in the energy-resolved experiment which indicates a strong contribution from inelastic scattering coming from correlated thermal displacements of the ions in the superionic phase. Diffraction experiments on a single crystal of alpha-Cu(1.8)Se have revealed an ordered structure with superstructure reflections at the G +/- 1/2 < 111 > and G +/- 1/3 < 220 > positions of reciprocal space at room temperature. In addition to superstructure spots, diffuse scattering was observed along the < 111 > direction which is considered as a possible diffusion path of mobile Cu ions. In inelastic neutron scattering measurements with this single crystal sample strong inelastic scattering was observed along < 111 >. This shows that the diffuse scattering found in conventional diffraction experiment is mainly inelastic and most probably comes from low-energy phonons. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
引用
收藏
页码:483 / 487
页数:5
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