中国物理B ›› 1993, Vol. 2 ›› Issue (3): 206-212.doi: 10.1088/1004-423X/2/3/006

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STUDIES ON THE BEHAVIOR OF THE INTERNAL VIBRATIONAL MODES IN (NH4)2TexSn1-xCl6 MIXED CRYSTALS

张家明a, 沈学础a, 周涛a, 谢韵宝a, 徐永晨b, 沈军b, 周佩珍b, J.PELZLc   

  1. Department of Physics, Xiamen University, Xiamen 361005, China
  • 收稿日期:1991-12-04 出版日期:1993-03-20 发布日期:1993-03-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China.

STUDIES ON THE BEHAVIOR OF THE INTERNAL VIBRATIONAL MODES IN (NH4)2TexSn1-xCl6 MIXED CRYSTALS

ZHANG JIA-MING (张家明)a, SHEN XUE-CHU (沈学础)a, ZHOU TAO (周涛)a, XIE YUE-BAO (谢韵宝)a, XU YONG-CHENb, SHEN JUN (沈军)b, ZHOU PEI-ZHEN (周佩珍)b, J.PELZLc   

  1. a National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Academia Sinica, Shanghai 200083, China; b Pohl Institute for Solid State Physics, Tongji University, Shanghai 200092, China; c Institute of Experimental Physics, Ruhr University, Bochum, D-4630. Germany
  • Received:1991-12-04 Online:1993-03-20 Published:1993-03-20

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摘要： The behavior of the internal lattice vibrational modes in (NH4)2TexSn1-xCl6 mixed crystals has been investigated by Raman scattering. All of the Raman-active [MX6]2- internal modes show two-mode property in the mixed crystals with compositions from x?=?0 to 1, and apart from the sample with x?=?0.5, their energy positions are composition-independent. Space group calculations including site symmetry considerations and frequency fittings describe a good force field model. It has been demonstrated that the composition-independent two-mode behavior may come from the strong clustering effect, rather than from the character of the gap and local modes of impurities in mixed crystals. For the sample with x?=?0.5, the two component elements seem to form a pseudo-periodic lattice structure.

Abstract: The behavior of the internal lattice vibrational modes in (NH4)2TexSn1-xCl6 mixed crystals has been investigated by Raman scattering. All of the Raman-active [MX6]2- internal modes show two-mode property in the mixed crystals with compositions from x=0 to 1, and apart from the sample with x=0.5, their energy positions are composition-independent. Space group calculations including site symmetry considerations and frequency fittings describe a good force field model. It has been demonstrated that the composition-independent two-mode behavior may come from the strong clustering effect, rather than from the character of the gap and local modes of impurities in mixed crystals. For the sample with x=0.5, the two component elements seem to form a pseudo-periodic lattice structure.

中图分类号: 

  • 6320D