Role of the Zhang-Rice-like exciton in optical absorption spectra of CuGeO 3 and CuGe 1-x Si x O 3 single crystals
Role of the Zhang-Rice-like exciton in optical absorption spectra of CuGeO 3 and CuGe 1-x Si x O 3 single crystals
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张米状激子在CuGeO 3 和CuGe 1-x Si x O 3 单晶光吸收光谱中的作用
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
G. Samoggia
中科院分区：
文献类型：
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作者：
S. Pagliara;F. Parmigiani;P. Galinetto;A. Revcolevschi;G. Samoggia
在15-300 K温度范围内研究了纯CuGeO 3和Si掺杂CuGeO 3的光激发。一个结构，检测到的E场平行于c轴的晶体在约3.2 eV，是由于形成的张赖斯样（ZR）激子。振子强度较弱是由于CuGeO 3的共边CuO 4片元之间类ZR激子的迁移率较低。类Zr的能量的温度依赖性的解释由涉及声子-电子相互作用或自旋有序的变化的重整化效应，而类Zr的激子强度与Si含量的增加被认为是从不同的杂交的Si-O键相对于Ge-O。
The optical excitations in pure and Si-substituted CuGeO 3 are investigated in the 15-300 K temperature range. A structure, detected for the E field parallel to the c axis of the crystals at about 3.2 eV, is due to the formation of a Zhang-Rice-like (ZR) exciton. The weak oscillator strength is due to the low mobility of the ZR-like exciton between the edge-sharing CuO 4 plaquettes of CuGeO 3 . The temperature dependence of the ZR-like energy is explained by a renormalization effect involving phonon-electron interactions or changes in spin ordering, while the increase of ZR-like exciton intensity with the Si content is argued to arise from a different hybridization of the Si-O bond with respect to Ge-O.