Comment on ``Raman spectroscopy study of Na x CoO 2 and superconducting Na x CoO 2 ∙yH 2 O '
Comment on ``Raman spectroscopy study of Na x CoO 2 and superconducting Na x CoO 2 ∙yH 2 O '
复制标题
对《Na x CoO 2 和超导 Na x CoO 2 ∙yH 2 O 的拉曼光谱研究》的评论
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
B. Keimer
中科院分区：
文献类型：
--
作者：
P. Lemmens;P. Scheib;Y. Krockenberger;L. Alff;F. Chou;C. Lin;H. Habermeier;B. Keimer
讨论了热电钴酸盐表面降解对拉曼光谱的影响，并与Co3O4单晶的实验结果进行了比较。我们得出结论，在NaCl通量下生长的NaxCoO2晶体容易形成表层Co3O4，导致在700 cm-1附近观察到强声子[物理学]。Rev. B 70, 052502(2004)]。光学浮区炉新切割晶体的拉曼光谱没有显示出这种效应，并且在大约600 cm -1处具有高频声子截止。[j].社会科学，2006(5)。讨论了热电钴酸盐的结构维数、电子相关和高频声子截止的关系。
The effect of surface degradation of the thermolectric cobaltite on Raman spectra is discussed and compared to experimental results from Co3O4 single crystals. We conclude that on NaCl flux grown NaxCoO2 crystals a surface layer of Co3O4 easily forms that leads to the observation of an intense phonon around 700 cm-1 [Phys. Rev. B 70, 052502 (2004)]. Raman spectra on freshly cleaved crystals from optical floating zone ovens do not show such effects and have a high frequency phonon cut-off at approximately 600 cm -1 [Phys. Rev. Lett 96, 167204 (2006)]. We discuss the relation of structural dimensionality, electronic correlations and the high frequency phonon cut-off of the thermolectric cobaltite.