Raman scattering by optical phonons in isotopic 70(Ge)n74(Ge)n superlattices.
Raman scattering by optical phonons in isotopic 70(Ge)n74(Ge)n superlattices.
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同位素 70(Ge)n74(Ge)n 超晶格中光学声子的拉曼散射。
DOI：
10.1103/physrevlett.72.1565
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发表时间：
1994
影响因子：
8.6
通讯作者：
Haller
中科院分区：
文献类型：
--
作者：
Spitzer;Ruf;Cardona;Dondl;Schorer;Abstreiter;Haller
我们给出了一系列具有2[LE][ITAL n][LE]32的同位素[SUP70](Ge)[SUP74](Ge)[SUP70][SUP74](Ge)[SUB[ITAL n]]超晶格的拉曼光谱。在这些新颖的结构中，只有声子受到周期性的同位素质量调制，而电子保持其块状特征。这与传统的超晶格有很大的不同，在传统的超晶格中，电子和振动性质都受到降维的影响。我们的结果表明，在这两个超晶格成分中都有明显的光学声子限制。观察到的频率、相对强度和模混合与基于平面键-电荷模型和键极化率方法的计算结果吻合较好。
We present Raman spectra of a series of isotopic [sup 70](Ge)[sub [ital n]][sup 74](Ge)[sub [ital n]] superlattices with 2[le][ital n][le]32. In these novel structures only the phonons are subject to a periodic isotopic mass modulation, whereas the electrons retain their bulklike character. This differs substantially from conventional superlattices where both electronic and vibronic properties are affected by the reduction in dimensionality. Our results show clear evidence for optic phonon confinement in each of the two superlattice constituents. Observed frequencies, relative intensities, and mode mixing compare favorably with calculations based on a planar bond-charge model and the bond polarizability approach.