OPTICAL PHONONS IN ISOTOPIC GE STUDIED BY RAMAN SCATTERING
OPTICAL PHONONS IN ISOTOPIC GE STUDIED BY RAMAN SCATTERING
复制标题
通过拉曼散射研究同位素 GE 中的光学声子
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
K. Itoh
中科院分区：
文献类型：
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作者：
Jie Zhang;M. Giehler;A. Göbel;T. Ruf;M. Cardona;E. Haller;K. Itoh
用拉曼光谱测定了同位素取代对同位素富集的${(}^{70}mathrm{Ge}$、${}^{73}mathrm{Ge}$、${}^{74}mathrm{Ge}$和${}^{76}mathrm{Ge}$和自然锗（${}^{70/76}mathrm{Ge}$）锗样品中$ensuremath{Gamma}$点声子的影响。我们认为，与早期的工作相反，只有当表面氧化物被化学蚀刻去除时，才能观察到本征体拉曼声子，并且使用红色的激光线来大大增强光的穿透深度。在这些条件下进行的10 K高分辨率实验中，我们获得了更精确的声子频率，并发现声子线宽比以前报道的明显减少。我们的观察结果改进了以前的结果，并且与相干势近似和超级单体计算的预测更加一致。
The effects of isotopic substitution on the $ensuremath{Gamma}$-point phonon in isotopically enriched ${(}^{70}mathrm{Ge}$, ${}^{73}mathrm{Ge}$, ${}^{74}mathrm{Ge}$, and ${}^{76}mathrm{Ge}$) and disordered (natural Ge and ${}^{70/76}mathrm{Ge}$) germanium samples have been measured with Raman spectroscopy. We believe, in contrast to earlier work, that intrinsic bulk Raman phonons are observed only when surface oxides are removed by chemical etching, and a laser line in the red is used to greatly enhance the penetration depth of the light. In high-resolution experiments at 10 K, performed under these conditions, we obtain more precise phonon frequencies and find significantly reduced phonon linewidths than reported before. Our observations improve on previous results, and are in better agreement with predictions of coherent-potential-approximation and supercell calculations.