Observation of T2-like coherent optical phonons in epitaxial Ge2Sb2Te5/GaSb(001) films
Observation of T2-like coherent optical phonons in epitaxial Ge2Sb2Te5/GaSb(001) films
复制标题
外延Ge2Sb2Te5/GaSb(001)薄膜中类T2相干光学声子的观察
作者：
A. Shalini;Y. Liu;U. Al;G. P. Srivastava;C. Wright;F. Katmis;Wolfgang Braun;R. Hicken
Ge2Sb2Te5 的声子谱是其晶体结构的特征，是存储器应用中使用的相变过程的基础。外延材料允许在飞秒各向异性反射测量中研究相干光学声子。在 GaSb(001) 上生长的外延 Ge2Sb2Te5 中观察到频率为 3.4 THz 的主声子模式。信号强度对泵浦和探针偏振的依赖性由瞬态受激拉曼散射理论描述，该理论通过使用拉曼张量解释了晶体结构的对称性。 3.4 THz 模式具有 Oh 点群预期的 3 维 T2 模式的特征，证实了基础晶体结构是立方的。应用大泵注量后，在 Ge2Sb2Te5 和 GaSb 中观察到新模式，并将其解释为与 Sb 偏析相关的一维和二维模式。
The phonon spectrum of Ge2Sb2Te5 is a signature of its crystallographic structure and underlies the phase transition process used in memory applications. Epitaxial materials allow coherent optical phonons to be studied in femtosecond anisotropic reflectance measurements. A dominant phonon mode with frequency of 3.4 THz has been observed in epitaxial Ge2Sb2Te5 grown on GaSb(001). The dependence of signal strength upon pump and probe polarization is described by a theory of transient stimulated Raman scattering that accounts for the symmetry of the crystallographic structure through use of the Raman tensor. The 3.4 THz mode has the character of the 3 dimensional T2 mode expected for the Oh point group, confirming that the underlying crystallographic structure is cubic. New modes are observed in both Ge2Sb2Te5 and GaSb after application of large pump fluences and are interpreted as 1 and 2 dimensional modes associated with segregation of Sb.
影响因子：
3.2
作者：
Liu, Y.;Aziz, M. M.;Hicken, R. J.
通讯作者：
Hicken, R. J.