Research on the thermal shifts and electron-phonon coupling parameters of R-line for Cr3+ and Mn4+ ions in YAlO3 crystals
Research on the thermal shifts and electron-phonon coupling parameters of R-line for Cr3+ and Mn4+ ions in YAlO3 crystals
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DOI：
10.1016/j.jlumin.2013.02.003
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发表时间：
2013-06
影响因子：
3.6
通讯作者：
Z. Wen-chen;Li Bang-Xing;Feng Guoying;Liu Hong-gang
中科院分区：
文献类型：
--
作者：
Z. Wen-chen;Li Bang-Xing;Feng Guoying;Liu Hong-gang
采用一个新的理论表达式，研究了YAlO 3晶体中等电子3d 3离子Cr ~（3+）和Mn ~（4+）的R线热位移，该表达式既考虑了晶格热膨胀的静态贡献，又考虑了电子-声子相互作用的振动贡献.新的表达式在形式上与以前文献中广泛使用的只包含振动贡献的表达式几乎相同，只是系数由α变为α′+A（其中α和α′分别为表观和真实的电子-声子耦合参数）. A是关于静态贡献的参数）。利用新的表达式和对R线的压力和温度依赖性的分析，发现静态对R线热位移的贡献在符号上与振动的相反，其大小约为振动的36%。结果表明，在YAlO 3晶体中，Cr 3+和Mn 4+的电子-声子耦合参数α′比相应的参数α增加了约36%。因此，为了合理地解释谱线的热位移和确定真实的电子-声子耦合参数，必须同时考虑静态和振动对热位移的贡献。电子-声子耦合参数|α′|讨论了Mn ~（4+）在YAlO_3晶体中的扩散比Cr ~（3+）大的问题。
The thermal shifts of R-line for isoelectronic 3d3ions Cr3+and Mn4+in YAlO3crystal are studied by using a new theoretical expression including both the static contribution due to lattice thermal expansion and the vibrational contribution due to electron–phonon interaction. The new expression in form is almost the same as that containing only the vibrational contribution (which is widely-used in the previous papers) except the change of coefficient from α to α′+A (where α, obtained from the old expression, and α′, obtained from the new expression, are the apparent and true electron–phonon coupling parameters, respectively. A is a parameter concerning the static contribution). By using the new expression and the analysis of pressure- and temperature-dependences of R-line, it is found that the static contribution to the thermal shift of R-line in sign is contrary to and in magnitude is about 36% of the vibrational one. Thus, the electron–phonon coupling parameters α′ increase about 36% compared with the corresponding parameters α for both Cr3+and Mn4+in YAlO3crystal. So, for the reasonable explanation of thermal shifts of spectral lines and the determination of the true electron–phonon coupling parameter, both the static and vibrational contributions to thermal shift should be taken into account. The reason that the electron–phonon coupling parameter |α′| of Mn4+is larger than that of Cr3+in YAlO3crystal is discussed.